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Student Name: ________________________________________________
Grade 8 Practice Test 4 Annotated
Mississippi Code 37-16-4 prohibits prior disclosure of the materials contained in this booklet to a student who will be taking this test. Mississippi Code also prohibits any person from releasing, causing to be released, reproducing or causing to be reproduced any secure materials in any form or medium. Violations of the statute may result in invalidation of test scores, suspensions of certificates to teach, and/or prosecution.
Mississippi Department of Education
Office of Student Assessment
Science Test
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 1 of 98
Grade 8
Strand Inquiry
Competency 1: Draw conclusions from scientific investigations including controlled
experiments.
PLD 1 a Proficient: Design, conduct, and analyze conclusions from an investigation
that includes using experimental controls.
DOK 3
1. Two students carried out an investigation in which they measured the evaporation rate
of water under different conditions. The following table summarizes their findings.
The students concluded that water evaporates most quickly at 85°F.
Why would a scientist question the validity of this conclusion?
A. More water evaporated at 95°F than at 85°F. B. The experiment did not control time of evaporation. C. The experiment did not control the initial volume of water. D. Temperature was a variable that should have been a constant.
Beaker Number 1
Temperature (ºF) 55
Starting Volume (mL) 45
Final Volume (mL) 30
Water Lost (mL) 15
Elapsed Time (hours) 24
2
65
50
30
20
24
3
75
50
20
30
24
4
85
55
15
40
24
5
95
45
10
35
24
Evaporation Rate of Water
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C is the correct answer.
There are four different starting volumes in this experiment; however, the
variable was supposed to be temperature. By using different starting
volumes, a second variable is introduced, creating the possibility for data to
be unreliable. One initial volume should be used, and the experiment
should be run again to find new data.
A is not the correct answer.
Based on the data, more water actually evaporated at 85°F than at 95°F.
The difference between the starting volume and final volume at 85°F is
40 mL, but it is only 35 mL at 95°F.
B is not the correct answer.
The elapsed time in the table was twenty-four hours for each beaker, which
means the time was controlled.
D is not the correct answer.
Temperature was the variable being tested in this experiment. Therefore, it
is not a controlled variable and should not be held constant.
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Grade 8
Strand Inquiry
Competency 1: Draw conclusions from scientific investigations including controlled
experiments.
PLD 1 a Advanced: Evaluate the design of an investigation, including the design’s use
of experimental controls and the design’s effect on the conclusion.
DOK 3
Bandaging Bacteria
Some bacteria are harmful, such as Staphylococcus and Pseudomonas. These bacteria release toxins that burst open human cells. They rob the cell of glucose, which they use for energy. This allows the bacteria to reproduce very quickly and go on to attack more human cells. Some bacteria are helpful, such as E. coli. These bacteria are important to human bodies because they produce vitamin K. They also help protect human cells by blocking the growth of disease-causing bacteria. Chemical compounds called antibiotics are used to destroy harmful types of bacteria. However, these antibiotics can also destroy useful bacteria such as E. coli, which is used to make one type of vitamin K. Vitamin K is needed to clot blood.
Scientists are working to develop a new kind of bandage that helps fight infections caused by harmful bacteria. The bandage material contains tiny capsules that look like human cells. Inside the capsules are antibiotics. When capsules in the bandage material are attacked by bacteria, they release antibiotics that destroy the bacteria on contact.
For his science project, Ben investigated the bandage material using three different types of bacteria. He followed these steps:
1) Filled four Petri dishes with nutrient gel and labeled them 1 through 4
2) Placed a swab in the Staphylococcus bacteria and rubbed the swab onto Petri dish 1, placing the lid on tightly
3) Used the same swab to repeat step 2 with Pseudomonas in Petri dish 2, placing the lid on tightly
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4) Used the same swab to repeat step 2 with E. coli in Petri dish 3, placing the lid on tightly
5) Did not place any bacteria in Petri dish 4, placing the lid on tightly
6) Placed all of the Petri dishes on a shelf, away from light and moisture for 24 hours
7) Placed equal amounts of the bandage material in each Petri dish
8) Placed all of the Petri dishes on a shelf, away from light and moisture for 36 hours
9) Repeated steps 1 through 8 for a total of three trials
The following table shows the results of the investigation.
Effects of Bandage Material on Bacterial Growth
PetriDish
Bacteria Added Description of Results after 36 Hours
1
2
3
4
Staphylococcus
Pseudomonas
E. Coli
None No bacteria present
Most bacteria destroyed Only small amount of bacteria remain
Most bacteria destroyed Only small amount of bacteria remain
Most bacteria destroyed Only small amount of bacteria remain
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2. Based on the data, Ben concluded that the material would be useful in hospitals
because it reduces the number of harmful bacteria. Which of these describes Ben’s conclusion?
F. The conclusion is valid because it is supported by accurate results. G. The conclusion is valid because the investigation was repeated three times. H. The conclusion may be invalid because there was no control in the investigation. J. The conclusion may be invalid because the same swab was used for all three
bacteria.
J is the correct answer.
By using the same swab to apply all three bacteria samples, Ben
contaminated dishes 2 and 3 with more than one type of bacteria.
Therefore, he cannot be certain that it is the bandage material affecting the
number of bacteria because there is more than one variable introduced.
Ben did not control all variables other than the one being tested, the
independent variable. Therefore, the experiment has a design flaw that
affects the validity of the conclusions.
F is not the correct answer.
The accuracy of the results can be questioned because not all variables
other than the one being tested, the independent variable, were controlled.
This design flaw affects the validity of the conclusion.
G is not the correct answer.
Ben did perform multiple tests, but he used the same swab to apply all
three strands of bacteria to the dishes. Although it is part of a good
experimental design to perform multiple tests, controlling all variables other
than the one being tested is also important. Using the same swab
introduces more than one variable to each dish and affects the validity of
the conclusion.
H is not the correct answer.
Petri dish 4 contained no bacteria and can then be considered the control
group, which is necessary for comparison of results. Because Ben used the
same swab for all three dishes, the bacteria added to each dish was not
controlled and is the factor that affects the validity of the conclusion.
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Grade 8
Strand Inquiry
Competency 1: Draw conclusions from scientific investigations including controlled
experiments.
PLD 1 b Proficient: Distinguish between qualitative and quantitative observations and
make inferences based on observations.
DOK 3
3. Meg investigated the ability of different plants to decrease soil erosion. She performed
the following steps: 1) Planted five different species of plants, each in its own box 2) Set up the boxes in the same manner with one end of each box propped up at the
same angle 3) Placed a collection device at the bottom of each box to catch soil runoff 4) Released water over each box in the same manner 5) Measured the amount of soil runoff and recorded the appearance of the water The following table shows Meg’s data.
Based on both quantitative and qualitative data, which is a logical inference for this
investigation? A. The less able the plant was to prevent soil erosion, the clearer the water and the less soil
that eroded. B. The cloudier the water, the more soil that eroded and the less able the plant was to
prevent soil erosion. C. The clearer the water, the more soil that eroded and the better able the plant was to
prevent soil erosion. D. The better able the plant was to prevent soil erosion, the cloudier the water and the more
soil that eroded.
Soil in Water After Erosion Tests
A
22
Verycloudy
B
7
Mostlyclear
C
13
Cloudy
D
5
Mostlyclear
E
20
Verycloudy
Sample
Amount of Soil inWater Runoff (grams)
Appearance of Water
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B is the correct answer.
This inference is based on both qualitative (the appearance of the water)
and quantitative (the amount of soil that eroded) observations. It is also
logical based on the data because more soil in the runoff is a sign of a
higher amount of soil erosion, meaning the plant was not able to prevent
soil erosion very well.
A is not the correct answer.
The inference is stated first. The sentence should be stated so that it is
clear that the results lead to the inference. Additionally, if a plant is less
able to prevent soil erosion, more soil would erode.
C is not the correct answer.
Clearer water would lead to an inference that the plant was better able to
prevent soil erosion. However, this would mean that less soil eroded.
D is not the correct answer.
The inference is stated first. The sentence should be stated so that it is
clear that the results lead to the inference. Additionally, if a plant is better
able to prevent soil erosion, less soil would erode.
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Grade 8
Strand Inquiry
Competency 1: Draw conclusions from scientific investigations including controlled
experiments.
PLD 1 b Basic: Identify an inference as being based on qualitative observations or
quantitative observations.
DOK 2
4. Ethan investigated which of three liquids had the highest boiling point. He put equal
amounts of liquid in different beakers and placed each beaker over the same amount of heat. To compare the liquids’ boiling points, he measured how long it took for each liquid to boil. The following table shows his results.
Ethan concluded that Liquid B had the highest boiling point.
Which of these led to this conclusion?
F. Qualitative observation of how hot the liquids got G. Quantitative measurement of how hot the liquids got H. Qualitative observation of how long it took for the liquids to boil J. Quantitative measurement of how long it took for the liquids to boil
Amount of Timefor Liquid to Boil
Time(seconds)
94
230
196
Liquid
A
B
C
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J is the correct answer.
The data shown in this table, the amount of time for the liquids to boil, is
based on numbers rather than descriptions. Therefore, the conclusion
Ethan made is based on quantitative measurements.
F is not the correct answer.
Ethan did not measure how hot the liquids got because he placed each
beaker over the same amount of heat. Additionally, this would be a
quantitative measurement rather than a qualitative observation.
G is not the correct answer.
This observation could not have led to Ethan’s conclusion. He did not
measure how hot the liquids got because he placed each beaker over the
same amount of heat.
H is not the correct answer.
The amount of time it took for the liquids to boil is numerical data, so this
represents quantitative measurements rather than qualitative observations.
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Grade 8
Strand Inquiry
Competency 1: Draw conclusions from scientific investigations including controlled
experiments.
PLD 1 c Proficient: Summarize data to show the cause and effect relationship
between qualitative and quantitative observations.
DOK 3
Roll with It
Tara and Cory investigated the motion of an object for a school science project. They
wanted to know whether ramp height affected the distance a toy car would roll. They used
a 30-centimeter long board for the ramp. For the first trial, they placed the board flat on the
floor. For the other trials, they propped the board up to 5-, 10-, and 15-centimeter heights.
For each trial, Tara placed the same 5-gram toy car at the top of the board. She released
the toy car and Cory measured the time, in seconds (s), the toy car traveled on the flat
floor until it stopped. Tara measured the distance the toy car traveled on the floor, in
centimeters (cm). Cory calculated the average speed during each trial in centimeters per
second . The following table shows all their data, and the graph shows the motion of
the toy car in Trial 2.
Toy Car Rolling Data
TrialRampangle
(degrees)
Distance(cm)
Time(s)
Rampheight(cm)
1
2
3
4
0.0
5.0
10.0
15.0
0.0
9.0
16.0
23.5
0.0
175.0
300.0
485.0
0.0
4.0
6.0
8.7
0 1 2 3 4 5
175
225
275
125
75
25
Time (s)
Dis
tan
ce (
cm)
Motion of Toy Carin Trial 2
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While setting up their investigation, Cory placed the 7-gram stopwatch on the floor in front
of the ramp during Trial 3. Tara accidentally bumped the ramp, causing the toy car to roll
down the ramp and hit the stopwatch, which was at rest. They moved the stopwatch,
repeated the trial, and recorded the data, as shown above.
5. Based on the data, what is the cause-and-effect relationship between the ramps and the
toy cars? A. The farther the toy cars rolled, the longer the ramps. B. The slower the toy cars, the greater the ramps’ angle. C. The shorter the ramps, the greater the speed of the toy cars. D. The greater the ramps’ angle, the farther the toy cars rolled.
D is the correct answer.
The data show the positive relationship between ramp angle and distance the
toy cars rolled. This is an accurate summary of the data.
A is not the correct answer.
The same board was used for all trials, which means that the length of the
ramp was not changed, so the data do not show a relationship between these
variables.
B is not the correct answer.
The data show that the average speed, found by dividing distance by time,
increases as the ramp angle increases.
C is not the correct answer.
The same board was used for all trials, which means the length of the ramp
was not changed, so the data do not show a relationship between these
variables.
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Grade 8
Strand Inquiry
Competency 1: Draw conclusions from scientific investigations including controlled
experiments.
PLD 1 c Advanced: Predict the effect of summarized data.
DOK 3
6. Benito studied magnetic fields. He learned that a magnetic field is created when an
electric current passes through a wire. He found the following data showing how the magnetic field strength changes with distance from the wire.
Benito wanted to know the magnetic strength 10 centimeters away from the wire. Which summary of data provides a logical prediction for Benito?
F. • The magnetic field strength increases as the distance from the wire increases.
• The field strength at 10 centimeters will be 1 microtesla. G. • The magnetic field strength decreases as the distance from the wire increases.
• The field strength at 10 centimeters will be 5 microteslas. H. • The magnetic field strength decreases linearly as the distance from the wire increases.
• The field strength at 10 centimeters will be 1 microtesla. J. • The magnetic field strength increases linearly as the distance from the wire increases.
• The field strength at 10 centimeters will be 5 microteslas.
Strength of Magnetic Field
Distance from Wire(centimeters)
0.5
1.0
2.0
3.0
5.0
17
10
100
50
25
Magnetic Field Strength(microtesla)
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G is the correct answer.
An inverse relationship between magnetic field strength and distance from
the wire is shown in the data. This relationship leads to a prediction that an
increase in distance from the wire by a factor of 2 results in a decrease in
field strength by a factor of 2.
F is not the correct answer.
The data do not support a direct relationship between distance from the
wire and magnetic field strength. Additionally, an increase in distance by a
factor of 2 will lead to a decrease in field strength by a factor of 2 rather
than 10.
H is not the correct answer.
The data do not support a linear relationship because for each equal
change in distance, the change in magnetic field strength is not the same.
Because the variables increase and decrease by the same factor, an
increase in distance by a factor of 2 will lead to a decrease in field strength
by a factor of 2 rather than 10.
J is not the correct answer.
The data support neither a direct nor a linear relationship. For each equal
increase in distance, the magnetic field strength decreases by a different
amount. However, the data do support the prediction that an increase in
distance by a factor of 2 will lead to a decrease in field strength by a factor
of 2.
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Grade 8
Strand Inquiry
Competency 1: Draw conclusions from scientific investigations including controlled
experiments.
PLD 1 d Proficient: Analyze evidence that is used to form explanations and draw
conclusions.
DOK 3
7. Bubbles form when an acid is mixed with baking soda, a base. Allie wanted to know
which household liquids are acids. She mixed several household liquids with two different white powders, baking soda and powdered sugar. The following data show her findings.
Which statement uses evidence from the table to form a conclusion? A. Water, milk, and dish soap must be acids because they did not form bubbles when
mixed with baking soda. B. Lemon juice and vinegar must be acids because they did not form bubbles when mixed
with powdered sugar. C. Water, milk, and dish soap must not be acids because they did not form bubbles when
mixed with baking soda. D. Lemon juice and vinegar must not be acids because they did not form bubbles when
mixed with powdered sugar.
LiquidForms Bubbles
with BakingSoda?
Forms Bubbleswith Powdered
Sugar?
Lemon juice
Water
Milk
Vinegar
Dish soap
Yes
No
No
Yes
No
No
No
No
No
No
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C is the correct answer.
The observations recorded in the table are accurately summarized. Given the
information that bubbles form when an acid is mixed with baking soda, it can
be concluded that any substances that do not form bubbles with baking soda
are not acids.
A is not the correct answer.
The observations are accurately summarized, but an incorrect conclusion is
drawn. Water, milk, and dish soap did not form bubbles with baking soda and
are therefore not acids.
B is not the correct answer.
This conclusion is based on the wrong set of observations. The information
given about acids refers to forming bubbles with baking soda, not powdered
sugar. Any substances that formed bubbles when mixed with baking soda
would be considered acids.
D is not the correct answer.
This conclusion is based on the wrong set of observations. The information
given about acids refers to forming bubbles with baking soda, not powdered
sugar. Any substances that did not form bubbles when mixed with baking
soda would not be considered acids.
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Grade 8
Strand Inquiry
Competency 1: Draw conclusions from scientific investigations including controlled
experiments.
PLD 1 d Basic: Identify evidence that supports an explanation or conclusion.
DOK 1
8. Jared investigated chemical reactions based on smell, color change, and release of
bubbles. What type of evidence would support any conclusion Jared makes?
F. An observation G. An estimation H. A calculation J. A measurement
F is the correct answer.
Jared used his senses to collect the evidence. Using the senses to collect
data is equivalent to making observations.
G is not the correct answer.
Estimations are calculated approximations based on numerical data. No
numerical data were gathered in this investigation.
H is not the correct answer.
Calculations are based on numerical data. No numerical data were gathered
in this investigation.
J is not the correct answer.
Measurements produce numerical data. No numerical data were gathered in
this investigation.
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Grade 8
Strand Inquiry
Competency 1: Draw conclusions from scientific investigations including controlled
experiments.
PLD 1 e Proficient: Develop a logical argument defending conclusions of an
experimental method.
DOK 3
9. A scientist measured the amounts of sulfurous gases near three active volcanoes and
three extinct volcanoes. He found that the areas near the active volcanoes had higher levels of sulfurous gases. Areas near the extinct volcanoes had limited amounts of sulfurous gases. The scientist concluded that an increase in sulfurous gases in the air surrounding a volcano is an indicator that a volcano is still active. Which of these is a logical argument defending the scientist’s conclusion?
A. He found little evidence that active volcanoes will become extinct. B. He did not take any samples from volcanoes that had erupted very recently. C. He found little evidence that extinct volcanoes produce sulfurous gases. D. He did not test any areas where there were not any volcanoes, active or extinct.
C is the correct answer.
This argument presents a fact (areas near the extinct volcanoes had limited
amounts of sulfurous gases) that supports the scientist’s conclusion (an
increase in sulfurous gases in the air surrounding a volcano is an indicator
that a volcano is still active).
A is not the correct answer.
This argument does not logically defend the conclusion based on the
investigation given. The scientist did not measure the amount of sulfurous
gases near the volcanoes over an extended period of time.
B is not the correct answer.
This argument does not defend the scientist’s conclusion. Information
presented in the investigation does not support this argument.
D is not the correct answer.
This argument does not defend the scientist’s conclusion. The comparison of
levels between extinct and active volcanoes does not require testing of air not
in the vicinity of volcanoes.
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Grade 8
Strand Inquiry
Competency 1: Draw conclusions from scientific investigations including controlled
experiments.
PLD 1 e Advanced: Justify whether an argument defending a conclusion is logical.
DOK 3
10. A tsunami is a powerful ocean wave caused by an earthquake. A tsunami rises greatly
in height as it nears land. Max used a tank of water to simulate the action of a tsunami. The following diagram shows his device.
Max concluded that a tsunami rises higher as it nears land because the water
becomes shallower closer to land. Which statement provides a logical defense for Max’s conclusion?
F. The simulated wave was made to be as powerful as possible. G. The tank was shallow enough to simulate the ocean near the shore. H. The tank had enough water in it to accurately simulate ocean waves. J. The bottom of the tank sloped upward at one end just like the bottom of the ocean near
the shore.
Earthquake-simulating
Device
Tsunami Tank
LandWater
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J is the correct answer.
This answer choice provides evidence that can be gathered from the
information given (specifically the diagram) as well as logical reasoning to
support the conclusion.
F is not the correct answer.
The power of the simulated wave was never indicated in this investigation and
is not relevant to the conclusion, so an argument based on this does not
provide support for the conclusion.
G is not the correct answer.
It was not the tank that got shallower closer to land; it was the water. This
argument does not provide reasoning that logically supports the conclusion.
H is not the correct answer.
The amount of water in the tank was never indicated in this investigation and
is not relevant to the conclusion, so an argument based on this does not
provide support for the conclusion.
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Grade 8
Strand Inquiry
Competency 1: Draw conclusions from scientific investigations including controlled
experiments.
PLD 1 f Proficient: Develop a logical argument to explain why perfectly designed
solutions do not exist.
DOK 3
11. Soils contain chemical nutrients that help plants grow. Different plants require
different amounts of nutrients. Scientists can test soil samples to determine how much of certain chemical nutrients are present. A manufacturer wants scientists to develop a soil in which any kind of plant could grow equally well. Which statement explains whether the ability to make this type of soil is possible?
A. Yes, most soils are those in which any kind of plant could grow. B. No, there is no way to tell what nutrients are needed by any kind of plant. C. Yes, a mixture of the soils that contained all the nutrients could nourish any plant. D. No, a soil in which certain kinds of plants grow well might not be as good for other types
of plants.
D is the correct answer.
Because the nutrients that support one plant may inhibit growth of another, it
is not likely that scientists would be able to find a soil that will allow all plants
to grow equally well. Therefore, this answer choice supports the idea that
perfectly designed solutions do not exist.
A is not the correct answer.
Although many soils may support the growth of several different types
of plants, it cannot be assumed that most soils could support all plant types.
B is not the correct answer.
It may be possible to determine what nutrients are needed by any kind of
plant, but it is not likely that scientists would be able to create a single soil to
accommodate the needs of all plants.
C is not the correct answer.
Because the nutrients that promote one plant’s growth may inhibit another
plant’s growth, it is not likely that scientists would be able to create a soil that
would support all kinds of plant growth if it contains all possible nutrients.
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Grade 8
Strand Inquiry
Competency 1: Draw conclusions from scientific investigations including controlled
experiments.
PLD 1 g Proficient: Justify a scientist’s need to revise conclusions after encountering
new experimental evidence that does not match existing
explanations.
DOK 3
12. Until recently, a certain type of fossil in rock beds was thought to be about 10,000
years old. A new, more accurate way of dating rock samples shows that it is actually 40,000 years old. However, this new evidence does not match scientists’ current explanations for how this species came to the area. Why should scientists revise their current explanations for how this species came to the area?
F. Fossils that are older than 10,000 years are extremely rare. G. Newer explanations are more correct than older explanations. H. The current explanations were based on less-accurate dating methods. J. Revising explanations every few years is a part of the scientific method.
H is the correct answer.
This response supports the idea that because of advances in technology and
science, scientists often need to investigate further and revise conclusions
after encountering evidence from more accurate research.
F is not the correct answer.
This response supports the older conclusion and does not provide a reason to
revise current explanations to support new findings.
G is not the correct answer.
A logical justification for revising findings is not provided. Scientists should
revise current explanations after investigating new findings and performing
further research when there is a contradiction to older explanations.
J is not the correct answer.
Scientists revise explanations when presented with newer, more accurate
evidence rather than at specific time intervals.
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Grade 8
Strand Inquiry
Competency 1: Draw conclusions from scientific investigations including controlled
experiments.
PLD 1 h Proficient: Analyze different ideas and recognize the skepticism of others as
part of the scientific process in considering alternative conclusions.
DOK 3
13. Dan wanted to know whether plants grow best in sunlight or artificial light. He set up
an investigation, making sure each plant received the same amount of light for the same amount of time. The following diagram shows his setup.
Dan found that the outside plants grew one inch taller than the inside plants. He
concluded that sunlight is better for plant growth than artificial light. A classmate, Carlos, is skeptical of Dan’s conclusion. Carlos thinks that Dan did not control other conditions that the plants grew under, such as temperature and available water. Which of these describes how Dan should respond to Carlos’s skepticism?
A. Dan should revise his original conclusion to match Carlos’s predictions about
temperature and air quality. B. Dan should dismiss Carlos’s criticism of his methods because Carlos did not carry out
the original experiment. C. Dan should invite Carlos to run the exact same experiment again to confirm that the
original conclusions are valid. D. Dan should run new tests to include other variables that Carlos mentioned to confirm
that the original conclusions are valid.
Group 1: Outside Group 2: Inside
Artificial lightSunlight
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D is the correct answer.
This response supports the idea that the skepticism of others is a necessary
part of the scientific process. Dan should address Carlos’s concerns by
running new tests in order to confirm the validity of his results and to allow for
alternative conclusions if necessary.
A is not the correct answer.
Carlos did not make any predictions. Rather, he presented skepticism that is a
necessary part of ensuring valid results. Dan should address Carlos’s
concerns by running additional tests.
B is not the correct answer.
Skepticism from others is a necessary part of the scientific process and
should be addressed to ensure valid results and to allow for alternative
conclusions if necessary.
C is not the correct answer.
This is not a logical response to Carlos’s skepticism. Because Carlos is
questioning part of the experimental design, running the same experiment
again would not address his concerns.
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Grade 8
Strand Inquiry
Competency 1: Draw conclusions from scientific investigations including controlled
experiments.
PLD 1 h Advanced: Evaluate arguments based upon the scientific process for ideas
presented as alternative conclusions.
DOK 3
14. When Alfred Wegener first proposed his theory of continental drift, most earth
scientists did not immediately accept it. Many expressed skepticism because the theory did not explain what force was strong enough to move continents. Later, scientists investigating continental drift found evidence that explained how continents are able to move. Plate tectonics, which grew from the theory of continental drift, now explains how continents move over time. How was the initial skepticism of earth scientists useful to the scientific process?
F. Skeptical comments showed that continental drift was not a correct explanation of
Wegener’s observations. G. The skeptics kept people from forgetting about earlier observations that did not support
continental drift. H. The scientists who were skeptical kept earth science from changing views too rapidly. J. The skeptics raised questions that became the starting point for new investigations.
J is the correct answer.
Skepticism was useful to the scientific process because new investigations
arose in response to questions raised about the theory of continental drift, and
those new investigations led to the new theory of plate tectonics.
F is not the correct answer.
No reason is offered as to why the initial skepticism was useful to the scientific
process. Skepticism alone does not mean an explanation is incorrect.
G is not the correct answer.
No reason is offered as to why the initial skepticism was useful to the scientific
process. The information provided does not mention skeptics keeping people
from forgetting about earlier observations that did not support continental drift.
H is not the correct answer.
No reason is offered as to why the initial skepticism was useful to the scientific
process. The information provided does not mention scientists who kept earth
science from changing views too rapidly. Skepticism should contribute toward
a useful check-and-balance process of inquiry, not slow down the process.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 25 of 98
Grade 8
Strand Inquiry
Competency 1: Draw conclusions from scientific investigations including controlled
experiments.
PLD 1 h Basic: Recognize appropriate scientific skepticism when reviewing
alternative conclusions.
DOK 2
Bandaging Bacteria
Some bacteria are harmful, such as Staphylococcus and Pseudomonas. These bacteria release toxins that burst open human cells. They rob the cell of glucose, which they use for energy. This allows the bacteria to reproduce very quickly and go on to attack more human cells. Some bacteria are helpful, such as E. coli. These bacteria are important to human bodies because they produce vitamin K. They also help protect human cells by blocking the growth of disease-causing bacteria. Chemical compounds called antibiotics are used to destroy harmful types of bacteria. However, these antibiotics can also destroy useful bacteria such as E. coli, which is used to make one type of vitamin K. Vitamin K is needed to clot blood.
Scientists are working to develop a new kind of bandage that helps fight infections caused by harmful bacteria. The bandage material contains tiny capsules that look like human cells. Inside the capsules are antibiotics. When capsules in the bandage material are attacked by bacteria, they release antibiotics that destroy the bacteria on contact.
For his science project, Ben investigated the bandage material using three different types of bacteria. He followed these steps:
1) Filled four Petri dishes with nutrient gel and labeled them 1 through 4
2) Placed a swab in the Staphylococcus bacteria and rubbed the swab onto Petri dish 1, placing the lid on tightly
3) Used the same swab to repeat step 2 with Pseudomonas in Petri dish 2, placing the lid on tightly
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 26 of 98
4) Used the same swab to repeat step 2 with E. coli in Petri dish 3, placing the lid on tightly
5) Did not place any bacteria in Petri dish 4, placing the lid on tightly
6) Placed all of the Petri dishes on a shelf, away from light and moisture for 24 hours
7) Placed equal amounts of the bandage material in each Petri dish
8) Placed all of the Petri dishes on a shelf, away from light and moisture for 36 hours
9) Repeated steps 1 through 8 for a total of three trials
The following table shows the results of the investigation.
Effects of Bandage Material on Bacterial Growth
PetriDish
Bacteria Added Description of Results after 36 Hours
1
2
3
4
Staphylococcus
Pseudomonas
E. Coli
None No bacteria present
Most bacteria destroyed Only small amount of bacteria remain
Most bacteria destroyed Only small amount of bacteria remain
Most bacteria destroyed Only small amount of bacteria remain
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 27 of 98
15. Ben presented his investigation to his lab partner, Kate. Kate is skeptical of the
results and listed the following concerns: 1) The results were repeated three times. 2) Ben used the same swab in three different bacteria. 3) Only one kind of bandage material was investigated. 4) Ben did not investigate other types of harmful bacteria. Which of Kate’s concerns support her skepticism?
A. 1 and 2 only B. 2 and 4 only C. 1, 2, and 3 only D. 1, 3, and 4 only
B is the correct answer.
Both the second and fourth concerns support Kate’s skepticism. Using the
same swab in three different bacteria is reason for concern of
contamination in dishes 2 and 3. This could then introduce variables other
than the one being tested, reducing the validity of the data. Additionally,
there are many different strands of harmful bacteria, so the results from
only three cannot be generalized to all strands.
A is not the correct answer.
The first concern does not support Kate’s skepticism. Repetition of results
is part of good experimental design.
C is not the correct answer.
The first and third concerns do not support Kate’s skepticism. Repetition of
results is part of good experimental design. Additionally, it would not be
appropriate for Ben to test more than one type of bandage material since
the point of his investigation was to test a specific bandage material.
D is not the correct answer.
The first and third concerns do not support Kate’s skepticism. Repetition of
results is part of good experimental design. Additionally, it would not be
appropriate for Ben to test more than one type of bandage material since
the point of his investigation was to test a specific bandage material.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 28 of 98
Grade 8
Strand Physical Science
Competency 2: Apply concepts relating to an understanding of chemical and physical
changes, interactions involving energy, and forces that affect motion of objects.
PLD 2 a Proficient: Identify patterns found in chemical symbols, formulas, reactions,
and equations that apply to the law of conservation of mass.
DOK 1
16. The following equation represents a balanced chemical reaction.
2Al2O3 + 3C 4Al + 3CO2 According to the law of conservation of mass, how many aluminum atoms will be
produced if 1,000 molecules of aluminum oxide are used in the reaction? F. 500 G. 1,000 H. 2,000 J. 4,000
H is the correct answer.
From the balanced equation given, the ratio of aluminum oxide to aluminum
(Al2O3:Al) is 2:4 or 1:2. Therefore, twice the number of aluminum oxide
molecules used gives the number of aluminum atoms produced.
F is not the correct answer.
This is the number of aluminum oxide (Al2O3) molecules that are used if 1,000
atoms of aluminum (Al) are produced.
G is not the correct answer.
If 1,000 molecules of a reactant are used, then 2,000 atoms will be produced,
not 1,000. Because the ratio for this reactant and product is actually 1:2, twice
as many aluminum atoms will be produced.
J is not the correct answer.
If 1,000 molecules of a reactant are used, then 2,000 atoms will be produced,
not 4,000. Because the ratio is 2:4 rather than 1:4, twice the number of
aluminum oxide molecules used gives the number of aluminum atoms
produced.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 29 of 98
Grade 8
Strand Physical Science
Competency 2: Apply concepts relating to an understanding of chemical and physical
changes, interactions involving energy, and forces that affect motion of objects.
PLD 2 a Advanced: Balance chemical equations to illustrate the law of conservation
of mass.
DOK 2
17. The following chemical equation shows the incomplete formula for burning methanol.
The question mark represents the unknown number of oxygen (O2) molecules.
2CH3OH + ?O2 2CO2 + 4H2O How many molecules of O2 are needed to balance this chemical equation? A. 1 B. 3 C. 5 D. 6
B is the correct answer.
The number of atoms of oxygen for each molecule in the equation can be
found by multiplying the coefficient on the molecule and the subscript on the
oxygen atom. Then, the atoms of oxygen from each molecule on each side
are added together. This produces eight atoms of oxygen on the reactant side
and eight atoms of oxygen on the product side.
A is not the correct answer.
A coefficient of 1 on the oxygen molecule would mean that 4 atoms of oxygen
would be present on the reactant side and 8 atoms of oxygen would be
present on the product side, which is an unbalanced equation.
C is not the correct answer.
A coefficient of 5 on the oxygen molecule would mean that 12 atoms of
oxygen would be present on the reactant side and 8 atoms of oxygen would
be present on the product side, which is an unbalanced equation.
D is not the correct answer.
A coefficient of 6 on the oxygen molecule would mean that 14 atoms oxygen
would be present on the reactant side and 8 atoms of oxygen would be
present on the product side, which is an unbalanced equation.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 30 of 98
Grade 8
Strand Physical Science
Competency 2: Apply concepts relating to an understanding of chemical and physical
changes, interactions involving energy, and forces that affect motion of objects.
PLD 2 a Basic: Identify the chemical symbols, formulas of common substances, or
reactions used in a balanced equation.
DOK 1
18. The following chemical equation shows the process of photosynthesis.
6CO2 + 6H2O C6H12O6 + 6O2 What is the common name of C6H12O6? F. Sugar G. Water H. Table salt J. Baking soda
F is the correct answer.
The chemical formula shown is for glucose, which is also known as sugar and
is one of the products of photosynthesis.
G is not the correct answer.
The chemical formula for water is H2O. Water is one of the reactants, not a
product, in photosynthesis.
H is not the correct answer.
The chemical formula for table salt is NaCl. This substance is not involved in
photosynthesis and is not present in the equation.
J is not the correct answer.
The chemical formula for baking soda is NaHCO3. This substance is not
involved in photosynthesis and is not present in the equation.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 31 of 98
Grade 8
Strand Physical Science
Competency 2: Apply concepts relating to an understanding of chemical and physical
changes, interactions involving energy, and forces that affect motion of objects.
PLD 2 b Proficient: Predict the properties and interactions of given elements using the
periodic table of the elements.
DOK 2
19.
Leroy combines magnesium (Mg) and fluorine (F). Based on the periodic table, which statement describes the interaction of these two elements?
A. Mg is a metal and F is a nonmetal that forms an ionic bond. B. Mg is a nonmetal and F is a metal that forms an ionic bond. C. Mg is a metal and F is a metal that forms a covalent bond. D. Mg is a metalloid and F is a nonmetal that forms a covalent bond.
1
HHydrogen
1.01
2
HeHelium
4.00
3
LiLithium
6.94
4
BeBeryllium
9.01
5
BBoron
10.81
6
CCarbon
12.01
7
NNitrogen
14.01
8
OOxygen
16.00
9
FFluorine
19.00
10
NeNeon
20.18
11
NaSodium
22.99
12
MgMagnesium
24.31
13
AlAluminum
26.98
14
SiSilicon
28.09
15
PPhosphorus
30.97
16
SSulfur
32.07
17
ClChlorine
35.45
18
ArArgon
39.95
19
KPotassium
39.10
20
CaCalcium
40.08
21
ScScandium
44.96
22
TiTitanium
47.88
23
VVanadium
50.94
24
CrChromium
52.00
25
MnManganese
54.94
26
FeIron
55.85
27
CoCobalt
58.93
28
NiNickel
58.69
29
CuCopper
63.55
30
ZnZinc
65.39
31
GaGallium
69.72
32
GeGermanium
72.61
33
AsArsenic
74.92
34
SeSelenium
78.96
35
BrBromine
79.90
36
KrKrypton
83.80
Group
Period
1
2
3
4
5
6
7
1
2
3 4 5 6 7 8 9 10 11 12
13 14 15 16 17
18
37
RbRubidium
85.47
38
SrStrontium
87.62
39
YYttrium
88.91
40
ZrZirconium
91.22
41
NbNiobium
92.91
42
MoMolybdenum
95.94
43
TcTechnetium
98.00
44
RuRuthenium
101.07
45
RhRhodium
102.91
46
PdPalladium
106.42
47
AgSilver
107.87
48
CdCadmium
112.41
49
InIndium
114.82
50
SnTin
118.71
51
SbAntimony
121.76
52
TeTellurium
127.60
53
IIodine
126.91
54
XeXenon
131.29
55
CsCesium
132.91
56
BaBarium
137.33
57
LaLanthanum
138.91
72
HfHafnium
178.49
73
TaTantalum
180.95
74
WTungsten
183.85
75
ReRhenium
186.21
76
OsOsmium
190.20
77
IrIridium
192.22
78
PtPlatinum
195.08
79
AuGold
196.97
80
HgMercury
200.59
81
TlThallium
204.38
82
PbLead
207.20
83
BiBismuth
208.96
84
PoPolonium
208.98
85
AtAstatine
210.00
86
RnRadon
222.00
87
FrFrancium
223.00
88
RaRadium
226.00
89
AcActinium
227.03
104
RfRutherfordium
(261)
105
DbDubnium
(262)
106
SgSeaborgium
(263)
107
BhBohrium
(264)
108
HsHassium
(265)
109
MtMeitnerium
(268)
Periodic Table of Elements
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 32 of 98
A is the correct answer.
Mg is on the left side of the periodic table and has a low electronegativity. F is
on the right side of the periodic table and has a high electronegativity.
Therefore, Mg is a metal, and F is a nonmetal. When they interact, Mg and F
will form an ionic bond because when a metal and a nonmetal form a bond,
the metal loses electrons while the nonmetal gains electrons due to the large
difference in their electronegativities.
B is not the correct answer.
Mg is on the left side of the periodic table and has a low electronegativity.
Elements that have very low electronegativities (and therefore have a
tendency to lose electrons) are classified as metals. F is on the right side of
the periodic table and has a high electronegativity. Elements that have very
high electronegativities (and therefore have a tendency to gain electrons) are
classified as nonmetals.
C is not the correct answer.
Two metals do not generally interact. Because F has a large electronegativity,
it is a nonmetal rather than a metal. Because of the large difference in their
electronegativities, Mg will lose electrons while F gains electrons, forming an
ionic bond.
D is not the correct answer.
Mg is a metal rather than a metalloid because it is on the far left side of the
periodic table and has a very low electronegativity. Metalloids are generally
found along the “stair-step” line that separates metals from nonmetals on the
periodic table. Additionally, metalloids have characteristics, such as
electronegativity, between that of metals and nonmetals. When Mg and F
interact, an ionic bond will be formed because of their large difference in
electronegativities.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 33 of 98
Grade 8
Strand Physical Science
Competency 2: Apply concepts relating to an understanding of chemical and physical
changes, interactions involving energy, and forces that affect motion of objects.
PLD 2 b Basic: Use the periodic table to identify the properties of an element or a
simple compound.
DOK 1
20. Christy is studying sodium in the following periodic table of elements.
She makes the following list of possible properties for sodium: • Symbol is Na • Is a transition metal • Atomic number is 11 • Has one valence electron Which of these should Christy remove from this list?
F. Symbol is Na G. Is a transition metal H. Atomic number is 11 J. Has one valence electron
Sodium in thePeriodic Table of Elements
1
2
3
4
5
6
7
1Group
Period
2
3 4 5 6 7 8 9 101112
1314151617
1811
NaSodium
22.99
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 34 of 98
G is the correct answer.
Transition metals are located in the short columns in the center of the periodic
table. This consists of columns 3 through 12. Sodium is a main group element
in the first column on the periodic table. The elements in this column are
considered alkali metals, not transition metals.
F is not the correct answer.
From the periodic table shown, the symbol for sodium is Na. The elemental
symbol is a capital letter that is sometimes, but not always, followed by a
lowercase letter and is located in the center of the box containing the
information for the element.
H is not the correct answer.
The atomic number is the number located above the elemental symbol in the
box containing the information for the element. From the periodic table shown,
this number is 11.
J is not the correct answer.
Sodium is located in the first column of the periodic table. All elements in this
column have one valence electron.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 35 of 98
Grade 8
Strand Physical Science
Competency 2: Apply concepts relating to an understanding of chemical and physical
changes, interactions involving energy, and forces that affect motion of objects.
PLD 2 c Proficient: Distinguish the motion of an object by its position, direction of
motion, speed, and acceleration and represent resulting data in
graphic form in order to make a prediction.
DOK 2
Roll with It
Tara and Cory investigated the motion of an object for a school science project. They
wanted to know whether ramp height affected the distance a toy car would roll. They used
a 30-centimeter long board for the ramp. For the first trial, they placed the board flat on the
floor. For the other trials, they propped the board up to 5-, 10-, and 15-centimeter heights.
For each trial, Tara placed the same 5-gram toy car at the top of the board. She released
the toy car and Cory measured the time, in seconds (s), the toy car traveled on the flat
floor until it stopped. Tara measured the distance the toy car traveled on the floor, in
centimeters (cm). Cory calculated the average speed during each trial in centimeters per
second . The following table shows all their data, and the graph shows the motion of
the toy car in Trial 2.
Toy Car Rolling Data
TrialRampangle
(degrees)
Distance(cm)
Time(s)
Rampheight(cm)
1
2
3
4
0.0
5.0
10.0
15.0
0.0
9.0
16.0
23.5
0.0
175.0
300.0
485.0
0.0
4.0
6.0
8.7
0 1 2 3 4 5
175
225
275
125
75
25
Time (s)
Dis
tan
ce (
cm)
Motion of Toy Carin Trial 2
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 36 of 98
While setting up their investigation, Cory placed the 7-gram stopwatch on the floor in front
of the ramp during Trial 3. Tara accidentally bumped the ramp, causing the toy car to roll
down the ramp and hit the stopwatch, which was at rest. They moved the stopwatch,
repeated the trial, and recorded the data, as shown above.
21. If the Trial 2 toy car had not stopped rolling and had continued in a straight line, how
far would the car have rolled at 5 seconds? A. 200 cm B. 225 cm C. 250 cm D. 275 cm
B is the correct answer.
The graph shows that with each second, the toy car traveled 50 cm. At 4 s,
the toy car traveled 175 cm; 175 cm 50 cm 225 cm.
A is not the correct answer.
The graph shows that with each second, the toy car traveled 50 cm. At 200
cm, the time that the toy car traveled is 4.5 s, not 5 s.
C is not the correct answer.
The graph shows that with each second, the toy car traveled 50 cm. At 250
cm, the time that the toy car traveled is 5.5 s, not 5 s.
D is not the correct answer.
The graph shows that with each second, the toy car traveled 50 cm. At 275
cm, the time that the toy car traveled is 6 s, not 5 s.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 37 of 98
Grade 8
Strand Physical Science
Competency 2: Apply concepts relating to an understanding of chemical and physical
changes, interactions involving energy, and forces that affect motion of objects.
PLD 2 c Advanced: Evaluate the motion of two or more objects to predict the effects of
a collision.
DOK 3
22. The following diagram shows the direction of motion of two objects of equal mass just
before they collide.
Which diagram shows the direction of motion of the two objects after they have
collided?
F.
H.
G.
J.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 38 of 98
F is the correct answer.
This is an example of conservation of momentum in an elastic collision. The
objects will collide, and an equal amount of energy will transfer between them,
causing each object to change its initial direction and move in the same
original direction as the object that collided with it.
G is not the correct answer.
The proper angle in which the collided objects will travel is not shown. They
will not move in straight, parallel lines.
H is not the correct answer.
Although the objects will travel away from each other, the vertical component
of their travel is not shown. They will not move in a straight line in opposite
directions from each other.
J is not the correct answer.
This response does not demonstrate the proper angle in which the collided
objects will travel. They will move apart but will not change direction in the
vertical plane because conservation of momentum must be followed.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 39 of 98
Grade 8
Strand Physical Science
Competency 2: Apply concepts relating to an understanding of chemical and physical
changes, interactions involving energy, and forces that affect motion of objects.
PLD 2 d Proficient: Relate how electrical energy transfers through electric circuits,
generators, and power grids, including the importance of
contributions from Mississippi companies.
DOK 2
23. The following image shows Device X, found in a power grid system.
What is the role of this device within the electrical grid system? A. It is a generator that produces the current needed inside the home. B. It is a distributor that diverts power from the distribution line to the home. C. It is a transformer that reduces the voltage between the power line and the home. D. It is a regulator that limits the amount of electric power in the wire to the home.
Device X
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 40 of 98
C is the correct answer.
The transformer steps down, or reduces, the voltage so that it is safe to enter
the home. The device shown is connected to power lines that supply
electricity to homes and performs this function.
A is not the correct answer.
The generator is located at the beginning of the power grid and is what
produces the electricity that flows through the grid. The device shown is
connected to power lines that supply electricity to homes and is therefore in a
different part of the power grid system.
B is not the correct answer.
The distributor is located at the substation and is what steps down the voltage
to a distribution level. The device shown is a transformer that will step down
the electricity once more before entering the home.
D is not the correct answer.
The regulator connects to the wires from the power lines and prevents
hazardous high- or low-voltage conditions. The device indicated is the larger,
cylindrical structure known as the transformer, and the regulators are the
smaller, spiral-shaped structures.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 41 of 98
Grade 8
Strand Physical Science
Competency 2: Apply concepts relating to an understanding of chemical and physical
changes, interactions involving energy, and forces that affect motion of objects.
PLD 2 d Advanced: Predict the outcome (positive or negative) of altering one
component of the power grid system.
DOK 3
24. A customer on a grid system installed a wind turbine.
What is the effect of this wind turbine on the entire power grid?
F. The addition of the turbine affects the customer but not the rest of the grid. G. The excess power would flow in the wrong direction in the grid, reducing the total
available power. H. The unused electric power can be added to the grid, increasing the power available to
other customers. J. The added power would overload the power grid and trip circuit breakers at the nearest
power substation.
H is the correct answer.
The excess energy produced by the turbine will need somewhere to go and
will therefore flow into the rest of the grid. When this happens, the power
available to anyone else connected to the grid will increase.
F is not the correct answer.
The turbine can affect the rest of the grid if there is excess power over what
the customer is currently using. Additional energy produced will flow into the
power grid.
G is not the correct answer.
The addition of the turbine will increase the total available power. At times
when the turbine is producing more power than the customer is using, that
additional power will flow into the power grid.
J is not the correct answer.
A single turbine will not produce enough energy to overload the power grid.
The energy available to other customers in the grid will simply increase.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 42 of 98
Grade 8
Strand Physical Science
Competency 2: Apply concepts relating to an understanding of chemical and physical
changes, interactions involving energy, and forces that affect motion of objects.
PLD 2 e Proficient: Contrast various components of the electromagnetic spectrum
(e.g., infrared, visible light, ultraviolet) and predict their impacts
on living things.
DOK 2
25. Infrared light is often used in reptile habitats.
Which of these explains how a reptile benefits from infrared light?
A. Infrared light destroys bacteria and other microorganisms. B. Infrared light increases the body temperature of the animals. C. Infrared light makes it possible for reptiles to see their surroundings. D. Infrared light makes it possible for humans to see the animals in their natural habitat.
B is the correct answer.
Reptiles are cold-blooded and absorb infrared light through their skin.
Infrared light bulbs are needed to supply this light to reptiles housed indoors.
A is not the correct answer.
Infrared light can dry out bacteria, but this is not the case with
microorganisms such as protists and fungi.
C is not the correct answer.
Some reptiles can see infrared light, but this is not the case with all reptiles.
In addition, reptiles are able to view their surroundings in visible light without
the aid of infrared light.
D is not the correct answer.
Humans are unable to see infrared light. In addition, humans are able to view
animals in visible light.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 43 of 98
Grade 8
Strand Physical Science
Competency 2: Apply concepts relating to an understanding of chemical and physical
changes, interactions involving energy, and forces that affect motion of objects.
PLD 2 e Basic: Identify components of the electromagnetic spectrum.
DOK 1
26. Ella is learning about different types of electromagnetic radiation. She makes the
following list about one frequency of radiation: • Can damage cells of living things • Blocked by Earth’s ozone layer Which type of radiation does Ella’s list describe?
F. Infrared G. Microwave H. Ultraviolet J. Visible
H is the correct answer.
Ultraviolet radiation has high energy with the ability to damage the cells of
living things and is considered hazardous in high doses. This type of radiation
is blocked by Earth’s ozone layer.
F is not the correct answer.
Infrared radiation is a type of low-frequency radiation with energy less than
that of visible light. It is not likely that radiation with low energy would damage
the cells of living things unless under prolonged exposure. Additionally, the
ozone layer is transparent to infrared but opaque to ultraviolet radiation.
G is not the correct answer.
Microwaves are a type of low-frequency radiation with energy less than that
of visible light. It is not likely that radiation with low energy would damage the
cells of living things. The ozone layer is transparent to microwave radiation.
J is not the correct answer.
Visible light does not have sufficient energy to be likely to damage the cells of
living things. Additionally, the ozone layer is transparent to visible light.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 44 of 98
Grade 8
Strand Physical Science
Competency 2: Apply concepts relating to an understanding of chemical and physical
changes, interactions involving energy, and forces that affect motion of objects.
PLD 2 f Proficient: Recognize Newton’s Three Laws of Motion and identify situations
that illustrate each law (e.g., inertia, acceleration, action, reaction
forces).
DOK 2
Roll with It
Tara and Cory investigated the motion of an object for a school science project. They
wanted to know whether ramp height affected the distance a toy car would roll. They used
a 30-centimeter long board for the ramp. For the first trial, they placed the board flat on the
floor. For the other trials, they propped the board up to 5-, 10-, and 15-centimeter heights.
For each trial, Tara placed the same 5-gram toy car at the top of the board. She released
the toy car and Cory measured the time, in seconds (s), the toy car traveled on the flat
floor until it stopped. Tara measured the distance the toy car traveled on the floor, in
centimeters (cm). Cory calculated the average speed during each trial in centimeters per
second . The following table shows all their data, and the graph shows the motion of
the toy car in Trial 2.
Toy Car Rolling Data
TrialRampangle
(degrees)
Distance(cm)
Time(s)
Rampheight(cm)
1
2
3
4
0.0
5.0
10.0
15.0
0.0
9.0
16.0
23.5
0.0
175.0
300.0
485.0
0.0
4.0
6.0
8.7
0 1 2 3 4 5
175
225
275
125
75
25
Time (s)
Dis
tan
ce (
cm)
Motion of Toy Carin Trial 2
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 45 of 98
While setting up their investigation, Cory placed the 7-gram stopwatch on the floor in front
of the ramp during Trial 3. Tara accidentally bumped the ramp, causing the toy car to roll
down the ramp and hit the stopwatch, which was at rest. They moved the stopwatch,
repeated the trial, and recorded the data, as shown above.
27. Which description applies to the toy car on Trial 1? A. An object at rest will stay at rest. B. For every action, there is an equal and opposite reaction. C. The rate at which an object falls is dependent upon the height from which the object is
dropped. D. The force needed to move an object is dependent upon the mass and acceleration of
the object.
A is the correct answer.
Newton’s first law of motion states that an object will continue to move at a
constant velocity unless acted on by an unbalanced force. The car in Trial 1
maintains a constant velocity of zero throughout the entire trial because it is
not acted on by any outside forces, such as gravity.
B is not the correct answer.
Newton’s third law of motion states that forces always come in action-reaction
pairs. This law does not apply to the car in Trial 1 because there is no action
force on the car.
C is not the correct answer.
Although the velocity at a particular point in time as an object is falling is
dependent on the height from which it is dropped, the rate at which an object
falls is always equal to the acceleration due to gravity. However, the car in
Trial 1 is at rest and is not being acted on by gravity.
D is not the correct answer.
Newton’s second law of motion is used to calculate the force acting on an
object. Because the car in Trial 1 is not moving and no force is acting on the
object, this law does not apply here.
Mississippi Department of Education Office of Student Assessment
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Grade 8
Strand Physical Science
Competency 2: Apply concepts relating to an understanding of chemical and physical
changes, interactions involving energy, and forces that affect motion of objects.
PLD 2 f Basic: Identify Newton’s Three Laws of Motion.
DOK 1
28. Which of these is one of Newton’s laws of motion? F. An object’s momentum is the product of its mass and velocity. G. A moving object will continue moving until a force acts upon it. H. The force of gravity is proportional to the inverse square of the distance. J. The rate at which an object falls depends on the height from which it is dropped.
G is the correct answer.
This is a restatement of Newton’s first law of motion, which says that an
object will move at a constant velocity until acted upon by an unbalanced
force.
F is not the correct answer.
This statement is true and is used while determining velocities before and
after a collision; however, it is not one of Newton’s laws of motion.
H is not the correct answer.
Although this statement is true, it is not one of the three Newtonian laws.
J is not the correct answer.
This statement is not one of Newton’s laws of motion and is stated
incorrectly. Although the velocity at a particular point in time as an object is
falling depends on the height from which it is dropped, the rate at which an
object falls is always equal to the acceleration due to gravity.
Mississippi Department of Education Office of Student Assessment
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Grade 8
Strand Life Science
Competency 3: Compare and contrast the structure and functions of the cell, levels of
organization of living things, basis of heredity, and adaptations that explain
variations in populations.
PLD 3 a Proficient: Analyze how adaptations to a particular environment can increase
an organism's survival and reproduction and relate organisms and
their ecological niches to evolutionary change and extinction.
DOK 3
29. A light-colored insect lives on trees in a forest. The bark of the trees appeared white
because of light-colored lichen that also lived on the tree. Disease destroyed the lichen. The tree bark is now dark-colored. How will this environmental change affect the number of light-colored insects?
A. The number of insects will decrease because, with the lichen gone, the insects will have
no other source of food. B. The number of insects will decrease because predators will see the light-colored insects
on the dark bark more easily. C. The number of insects will increase because, with the lichen gone, the insects will no
longer have to compete with the lichen for space. D. The number of insects will increase because the insect predators that also eat the
diseased lichen will become ill and decrease in number.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 48 of 98
B is the correct answer.
The light-colored lichen formed a covering that allowed the insects to be
camouflaged from predators. With the lichen gone, the insects will be easily
seen and preyed upon more often, decreasing the numbers in their
population.
A is not the correct answer.
There is no indication that the lichen was a food source for the insects.
Because the lichen forms a covering that allows the insects to be
camouflaged, it is more likely that this change will affect the insects’ ability to
hide from predators.
C is not the correct answer.
It is not likely that the insects were competing for space with the lichen.
Lichen form a covering that allows the insects to be camouflaged and
lessens predation.
D is not the correct answer.
It is not likely that the same predators that eat the insects will also eat the
lichen. Additionally, it cannot be assumed that a disease that affects lichen
will also affect organisms of a different species.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 49 of 98
Grade 8
Strand Life Science
Competency 3: Compare and contrast the structure and functions of the cell, levels of
organization of living things, basis of heredity, and adaptations that explain
variations in populations.
PLD 3 b Proficient: Compare and contrast the major components and functions of
different types of cells.
DOK 2
30. Chloroplasts are organelles that are found in plant cells. Some plant tissue contains
cells with large numbers of chloroplasts, while other tissue contains few chloroplasts. Which type of plant tissue contains cells with many chloroplasts?
F. Stem, because chloroplasts are needed for plant growth G. Root, because chloroplasts are needed for water uptake H. Leaf, because chloroplasts are needed for photosynthesis J. Flower, because chloroplasts are needed for reproduction
H is the correct answer.
The role of chloroplasts is to create sugars through the process of
photosynthesis. This process relies on the absorption of sunlight. Because
the leaves are the part of a plant with the most exposure to direct sunlight,
the cells in this tissue contain the largest number of chloroplasts.
F is not the correct answer.
Some plant stems do contain chloroplasts. However, the majority of
chloroplasts are located in the leaves, which are structured to absorb light.
Additionally, chloroplasts do not play a direct role in plant growth.
G is not the correct answer.
Roots are necessary for water absorption, and chloroplasts need water to
make sugars. However, chloroplasts do not play a direct role in water
absorption.
J is not the correct answer.
Chloroplasts do not directly contribute to reproduction.
Mississippi Department of Education Office of Student Assessment
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Grade 8
Strand Life Science
Competency 3: Compare and contrast the structure and functions of the cell, levels of
organization of living things, basis of heredity, and adaptations that explain
variations in populations.
PLD 3 b Basic: Identify different cell types and their structures.
DOK 1
31. Chris viewed the following cell through a microscope lens.
Which type of cell is Chris observing? A. Nerve cell B. Bone cell C. Blood cell D. Muscle cell
Nucleus
Dendrite
Cell body
Axon
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 51 of 98
A is the correct answer.
The dendrites and axons shown are specialized extensions that allow this
type of cell to carry impulses long distances. Because the role of nerve cells is
to transport messages between the brain and other parts of the body, the
extensive branching and structures shown support the function of a nerve cell.
B is not the correct answer.
The function of bone cells is to create new bone. Therefore, bone cells often
contain multiple nuclei as a result of cells fusing together.
C is not the correct answer.
The function of blood cells is to carry oxygenated blood throughout the body.
Because of this, blood cells are often small and do not contain a nucleus so
that they can hold as much hemoglobin as possible but can also squeeze
through small blood vessels.
D is not the correct answer.
The function of muscle cells is to allow movement. To do this, they must
create a large amount of energy. Therefore, muscle cells contain many
mitochondria. Additionally, they are usually packed together tightly to transfer
movements.
Mississippi Department of Education Office of Student Assessment
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Grade 8
Strand Life Science
Competency 3: Compare and contrast the structure and functions of the cell, levels of
organization of living things, basis of heredity, and adaptations that explain
variations in populations.
PLD 3 c Proficient: Describe how viruses, bacteria, fungi, and parasites may infect the
human body and interfere with normal body functions.
DOK 1
32. Which of these describes a pathogen that infects a human by injecting its DNA into a
body cell? F. A parasite that robs the cell of nutrients, interfering with organ functions G. A bacterium that creates a toxin that destroys the cell, keeping the cell from working in a
normal manner H. A fungus that eats keratin found in skin cells, causing inflammation and interfering with
the skin tissues’ ability to protect J. A virus that changes the way a cell works, causing the cell to make more viruses instead
of performing its intended function
J is the correct answer.
Viruses interfere with cell functioning by injecting their DNA into host cells.
The virus takes over protein manufacture and produces viral proteins to
create more viruses because viruses cannot reproduce on their own.
F is not the correct answer.
Parasites do not inject DNA into body cells. Parasites live in or on the host,
robbing the host of nutrients.
G is not the correct answer.
Bacteria do not inject DNA into body cells. The toxins created by bacteria are
by-products of their metabolism and do not contain bacterial DNA.
Additionally, toxins are not injected into host cells but rather interfere with
normal functioning by being present in the human body.
H is not the correct answer.
Fungi do not inject DNA into body cells. Fungi eat substances found in host
cells, causing irritation and improper functioning of cells.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 53 of 98
Grade 8
Strand Life Science
Competency 3: Compare and contrast the structure and functions of the cell, levels of
organization of living things, basis of heredity, and adaptations that explain
variations in populations.
PLD 3 d Proficient: Describe heredity as the passage of instructions from one
generation to another and recognize that hereditary information is
contained in genes, located in the chromosomes of each cell.
DOK 2
33. Lisa notices that her pet rabbits have similar fur color to their parents. Lisa draws the following diagram to show how fur color passes from the parents to the offspring.
Which offspring description will complete the diagram? A. • Offspring receives two DNA strands from each parent.
• DNA strands contain chromosomes. • Chromosomes from Parent 1 determine appearance of fur.
B. • Offspring receives half of DNA strand from each parent.
• Each half of DNA strand connects to form chromosome. • One chromosome determines appearance of fur.
C. • Offspring receives a set of two chromosomes, one from each parent.
• Chromosomes contain DNA strands. • DNA strands contain genes. • A pair of genes determines appearance of fur.
D. • Offspring receives a set of two chromosomes, one from each parent.
• Chromosomes contain genes. • Genes contain DNA strands. • Two sets of DNA strands determine appearance of fur.
Offspring
?
Parent 1
Gene for fur color is locatedon DNA strand;
DNA is coiled into chromosomewithin a cell.
Parent 2
Gene for fur color is locatedon DNA strand;
DNA is coiled into chromosomewithin a cell.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 54 of 98
C is the correct answer.
Chromosomes are made up of coiled strands of DNA. Within the strands of
DNA, specific sequences compose genes. When the offspring receives a
chromosome from each parent, the pair of genes will determine the trait.
A is not the correct answer.
Offspring would not receive two DNA strands from each parent because
this would cause offspring to have twice the amount of genetic material as
is appropriate for the organism. Additionally, DNA makes up chromosomes
rather than containing them. Appearance of fur color is dictated by a pair of
genes located on each chromosome received from each parent.
B is not the correct answer.
Offspring receives a set of chromosomes, one from each parent. Each
chromosome is made up of coiled, double-helix-shaped DNA strands
containing specific sequences called genes. A pair of genes, one from each
chromosome, determines the appearance of fur.
D is not the correct answer.
Chromosomes are made up of coiled strands of DNA, and DNA strands
contain specific sequences called genes. When the offspring receives a
chromosome from each parent, the pair of genes located on the DNA
strands will determine the trait.
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Grade 8
Strand Life Science
Competency 3: Compare and contrast the structure and functions of the cell, levels of
organization of living things, basis of heredity, and adaptations that explain
variations in populations.
PLD 3 d Advanced: Analyze a pedigree diagram to predict the inheritance for a
particular trait for a family member.
DOK 3
34. Some people are unable to see red and green colors. This condition, colorblindness, is
a recessive trait carried on the X chromosome, Xb. The following pedigree shows a family in which some individuals are affected by colorblindness.
Family members 6 and 7 in Generation II are expecting a son. The father’s genotype is XBY, while the mother’s is XBXb, as shown in the Punnett square. Which of the following describes the possibility of this son being colorblind?
F. Zero percent, because the father is not colorblind
G. Twenty-five percent, because in the Punnett square, only one box out of four shows an affected male
H. Fifty percent, because only one of the two males in the Punnett square has the genotype for being affected
J. One hundred percent, because the mother will pass the colorblindness trait to all offspring through her X chromosome
Family Pedigree Showing Colorblindness Trait
1
I
II
III
2
1 2 3 4 5 6 7
1 2
XB
XB
Y
Xb
3
?
= unaffected male
= unaffected female
= affected male
= carrier female
Key
XBXB XBXb
XBY XbY
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 56 of 98
H is the correct answer.
This takes gender into account and correctly interprets the meaning of the
recessive trait. Because the couple already knows they are having a son
and the Punnett square shows two possibilities for a son, the one box
showing an affected male represents 50% of the possibilities.
F is not the correct answer.
This would be the percentage if neither parent had the recessive gene. The
father is not colorblind and does not have the recessive gene. However, the
mother is a carrier. According to the Punnett square, there is a 50% chance
that the couple will have a son who is colorblind.
G is not the correct answer.
This would be the percentage if the gender was not specified. Because the
couple already knows they are having a son and the Punnett square shows
two possibilities for a son, the one box showing an affected male
represents 50% of the possibilities.
J is not the correct answer.
This would be the percentage if the mother were colorblind and had two
recessive genes. Because the mother is a carrier, she has a 50% chance
that she will pass on the recessive gene to a child. According to the
Punnett square, there is a 50% chance that the couple will have a son who
is colorblind.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 57 of 98
Grade 8
Strand Life Science
Competency 3: Compare and contrast the structure and functions of the cell, levels of
organization of living things, basis of heredity, and adaptations that explain
variations in populations.
PLD 3 e Proficient: Explain energy flow in a specified ecosystem.
DOK 2
35. The following diagram shows an energy pyramid for a wetland in Mississippi.
Which conclusion is supported by this diagram? A. River otters are tertiary consumers and have the least energy available to them. B. Crayfish are secondary consumers and have the most energy available to them. C. Phytoplankton are primary producers and have the least energy available to them. D. Zooplankton are secondary producers and have the most energy available to them.
Energy Pyramid of Mississippi Wetland
Phytoplankton
Zooplankton
Crayfish
River Otter
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 58 of 98
A is the correct answer.
Because river otters get energy from an organism that consumes
herbivores, they are considered tertiary consumers. Additionally, as energy
flows from producer to the top consumer, energy is lost at each step. In this
pyramid, river otters are the last consumers listed and therefore have the
least amount of energy available to them.
B is not the correct answer.
Because crayfish get energy from herbivores (organisms that consume only
producers), they are considered secondary consumers. However, energy
decreases as it flows from organism to organism in the food chain, so
crayfish have less energy available to them than zooplankton and
phytoplankton.
C is not the correct answer.
Because phytoplankton make their own energy from the sun and are
autotrophic, they are considered primary producers. However, they have
the most energy available to them because energy decreases as it flows
from organism to organism in the food chain, and phytoplankton do not
receive energy from another organism.
D is not the correct answer.
Because zooplankton get energy from producers (phytoplankton) and do
not create their own energy from the sun, they are considered primary
consumers rather than secondary producers. Additionally, as energy flows
from organism to organism in the food chain, energy is lost. Because
zooplankton receive energy from another organism, they do not have the
most energy available to them.
Mississippi Department of Education Office of Student Assessment
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Grade 8
Strand Life Science
Competency 3: Compare and contrast the structure and functions of the cell, levels of
organization of living things, basis of heredity, and adaptations that explain
variations in populations.
PLD 3 e Advanced: Analyze the food web of an ecosystem in which the population of
an organism has been altered to explain how this change may
affect another member of the food web ecosystem.
DOK 3
36. The following diagram shows a food web for a large lake.
The number of trout in the lake decreased due to overfishing by humans. Which statement describes the impact of this change on the other organisms in the food web?
F. The number of forage fish will decrease since they will have fewer trout upon which to prey.
G. The number of plankton will increase since fewer organisms will be getting energy from them.
H. The eagles will lose a source of energy and need to get energy from gulls, forage fish, and snapping turtles.
J. The snapping turtles will lose a source of energy and will need to get energy from gulls, eagles, and waterfowl.
Lake Food Web
Eagle Human
Trout
Gull
Forage Fish Waterfowl
SnappingTurtle
Vegetation
Plankton
Decaying Plant Material
Bacteriaand Fungi
Invertebrates
Mississippi Department of Education Office of Student Assessment
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H is the correct answer.
Eagles receive energy from gulls, forage fish, trout, and snapping turtles. A
decrease in the trout population would not cause much of a change in the
eagle population because these organisms will switch to receiving energy
from their other remaining sources.
F is not the correct answer.
The forage fish population would increase rather than decrease because
trout are consumers of forage fish, so there would be fewer organisms that
prey upon them.
G is not the correct answer.
The plankton population would decrease rather than increase because the
change would lead to an increase in the forage fish population. Because
forage fish consume plankton, there would be more organisms getting their
energy from plankton.
J is not the correct answer.
Snapping turtles do not consume larger, predatory fish such as trout. From
the diagram, snapping turtles receive their energy from forage fish only, so
they will not need to change their food source.
Mississippi Department of Education Office of Student Assessment
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Grade 8
Strand Life Science
Competency 3: Compare and contrast the structure and functions of the cell, levels of
organization of living things, basis of heredity, and adaptations that explain
variations in populations.
PLD 3 f Proficient: Develop a logical argument for or against research conducted in
selective breeding and genetic engineering, including research
conducted in Mississippi.
DOK 3
37. A bacterium, Bacillus thuringiensis (Bt), makes a toxin that destroys the larvae of
insects that threaten corn crops. Scientists engineered corn plants, known as Bt-corn. Bt-corn can make a toxin to destroy the larvae that eat the corn. Which of these supports the argument to stop production of genetically engineered Bt-corn?
A. Bt-corn pollen may harm helpful insects that pollinate the corn, such as bees. B. Bt-corn kernels may attract unwanted animals that can damage the crop, such as crows. C. Bt-corn plants use much less pesticide than unmodified corn plants. D. Bt-corn seed is more expensive than unmodified corn seed.
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A is the correct answer.
If the toxin created by Bt-corn is toxic to insect larvae, it can be assumed that
it may also be harmful to full-grown insects. Although some insects may be
detrimental to plant growth, there are many that are essential to the plants’
reproduction cycle, such as bees. Harming these insects is a logical concern
that could support stopping the production of Bt-corn.
B is not the correct answer.
There is no evidence in the scenario given to support this concern. The toxin
produced by Bt-corn is said to be harmful to insect larvae, but it cannot be
assumed that it would have an effect on other animals.
C is not the correct answer.
Using less pesticide due to the use of the genetically modified corn would be
beneficial to the environment. If true, this concern would provide support for
continuing to produce Bt-corn rather than stopping it.
D is not the correct answer.
An increase in seed price may be offset by a reduction in other costs, such
as pesticide and the fuel to apply it to the fields. The net result may actually
be that modified seed is less expensive overall.
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Grade 8
Strand Life Science
Competency 3: Compare and contrast the structure and functions of the cell, levels of
organization of living things, basis of heredity, and adaptations that explain
variations in populations.
PLD 3 f Basic: Identify examples of selective breeding or genetic engineering.
DOK 1
38. Which activity is an example of selective breeding? F. Collecting wild saplings from a forest and replanting them G. Cross-pollinating plants that produce large numbers of fruit H. Allowing a population of laboratory mice to mate randomly J. Raising sheep that have been cloned from adult sheep tissues
G is the correct answer.
Cross-pollinating involves selecting parents with the genes for desired traits
and breeding, through pollination. The desired trait, producing large numbers
of fruit, will be exhibited by the offspring as a result of this selective breeding.
F is not the correct answer.
This activity describes altering the habitat of an organism but does not
involve breeding. For a process to be considered selective breeding, two
parents with particular genes must be intentionally bred to produce the
desired trait.
H is not the correct answer.
This activity involves the process of sexual reproduction as it occurs
naturally, without selection by humans. For a process to be considered
selective breeding, two parents with particular genes must be intentionally
bred to produce the desired trait.
J is not the correct answer.
This activity describes the process of cloning, which involves producing
genetically identical offspring from one parent. For a process to be
considered selective breeding, two parents with particular genes must be
intentionally bred to produce the desired trait.
Mississippi Department of Education Office of Student Assessment
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Grade 8
Strand Life Science
Competency 3: Compare and contrast the structure and functions of the cell, levels of
organization of living things, basis of heredity, and adaptations that explain
variations in populations.
PLD 3 g Proficient: Research and draw conclusions about the use of single-celled
organisms in industry and in the production of food and about their
impact on life.
DOK 3
39. Bacteria on the roots of soybean plants are able to change nitrogen from the air into a
form usable by plants. Scientists have engineered other plants to support the growth of these nitrogen-fixing bacteria. Which of these describes a benefit of this research?
A. The need for space will decrease, allowing more land to be available for other crops. B. The need for water will decrease, allowing more water to be available for other crops. C. The need for fertilizer will decrease, reducing both the amount of fertilizer runoff and the
algae growth in streams and ponds. D. The need for pesticides will decrease, reducing both the amount of chemicals applied to
crops and the pollution of the water table.
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C is the correct answer.
This is a logical inference based on the information given. Fertilizers help
optimize plant growth by providing essential nutrients. Because the plants
would be better able to obtain some of these nutrients on their own, the need
for fertilizer would most likely decrease. This would be beneficial for the
environment because it would reduce the harmful effects caused by the
chemicals in fertilizer.
A is not the correct answer.
This response does not provide a logical inference based on the information
given. If soybean plants are better able to use the nitrogen from the air, it
would be expected that an increase, rather than a decrease, in plant growth
would occur due to the increase in available nutrients.
B is not the correct answer.
This response does not make a logical inference based on the information
given. An increase in the ability of soybean plants to use nitrogen from the air
would not necessarily mean they would have less of a need for other
essential nutrients such as water.
D is not the correct answer.
The response does not provide a logical inference based on the information
given. The use of pesticides does not contribute to nitrogen fixation and
would therefore not be affected by this type of genetic engineering.
Mississippi Department of Education Office of Student Assessment
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Grade 8
Strand Life Science
Competency 3: Compare and contrast the structure and functions of the cell, levels of
organization of living things, basis of heredity, and adaptations that explain
variations in populations.
PLD 3 g Basic: Identify examples of single-celled organisms that are used in
industry or food production or that impact life.
DOK 1
40. Which statement describes how a single-celled organism helps make a food product? F. Viruses that cause diseases are weakened and used to make vaccines. G. Yeast changes carbohydrates into carbon dioxide to make dough rise. H. Fungi release a chemical that keeps bacteria colonies from growing larger. J. Bacteria eat oil spilled in rivers and change it into less dangerous compounds.
G is the correct answer.
This response describes both a single-celled organism and its use in food
production.
F is not the correct answer.
Although it is true that viruses can be used in this manner, this answer choice
does not describe a food product. Additionally, viruses are not considered to
be living and are therefore not single-celled organisms.
H is not the correct answer.
This process may be beneficial in medicine, but the response does not show
how it would be used to help make a food product.
J is not the correct answer.
Although bacteria are single-celled organisms, this response does not describe
how they would be used to make a food product.
Mississippi Department of Education Office of Student Assessment
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Grade 8
Strand Life Science
Competency 3: Compare and contrast the structure and functions of the cell, levels of
organization of living things, basis of heredity, and adaptations that explain
variations in populations.
PLD 3 h Proficient: Describe how an organism gets energy from oxidizing its food and
releasing some of its energy as heat.
DOK 1
41. Food is digested and then delivered to body cells.
Which of these describes how the cells respond?
A. The cells absorb the energy in food through photosynthesis. B. The cells convert the food into nutrients through fermentation. C. The cells use the food and oxygen to make energy and release heat. D. The cells use the food to make heat energy through anaerobic respiration.
C is the correct answer.
Organisms get energy by oxidizing food. This process is carried out in body
cells and is called cellular respiration. During cellular respiration, sugar in the
food is broken down using oxygen, and carbon dioxide, water, and energy are
produced. The excess energy produced is then released by the cell as heat.
A is not the correct answer.
Photosynthesis is the process in which plants create food using energy from
the sun. Plant cells then use the process of cellular respiration to release the
energy in the food.
B is not the correct answer.
Fermentation is the process in which sugar in food is broken down in the
absence of oxygen to produce some energy and waste products, not
nutrients.
D is not the correct answer.
Anaerobic respiration is the process in which sugar in food is broken down in
the absence of oxygen to produce some energy and waste products.
Mississippi Department of Education Office of Student Assessment
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Grade 8
Strand Life Science
Competency 3: Compare and contrast the structure and functions of the cell, levels of
organization of living things, basis of heredity, and adaptations that explain
variations in populations.
PLD 3 h Advanced: Explain the process of cellular respiration to the survival of the cell
and its components.
DOK 3
42. Which of these describes how the absence of mitochondria would affect a cell? F. Heat would build up and cause the cell to become dehydrated because mitochondria
release energy. G. Toxins would collect and slow the production of ATP because mitochondria remove
waste from cells. H. Cells would be unable to undergo cellular respiration because mitochondria convert
glucose into energy. J. Cells would be unable to undergo fermentation because mitochondria convert
carbohydrates into sugars.
H is the correct answer.
Mitochondria are the part of the cell in which cellular respiration occurs. This
is the process by which the cell converts glucose, or sugar, into energy.
Without mitochondria, the cell would lack the energy necessary to perform
vital functions.
F is not the correct answer.
Mitochondria produce energy for the cell. Without them, the cell would lack
the energy necessary to perform functions essential to survival. Heat is
released when there is excess energy produced. This would not occur if there
was no energy being produced.
G is not the correct answer.
Mitochondria do not remove waste from cells. Rather, they produce energy.
Without mitochondria, the cell would not be able to produce ATP and would
therefore not be able to perform functions essential to survival.
J is not the correct answer.
Mitochondria do not convert carbohydrates into sugars. They convert sugar
into energy through cellular respiration. Without mitochondria, the cell would
lack the energy necessary to perform essential life functions.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 69 of 98
Grade 8
Strand Life Science
Competency 3: Compare and contrast the structure and functions of the cell, levels of
organization of living things, basis of heredity, and adaptations that explain
variations in populations.
PLD 3 h Basic: Identify the reactants and products involved in cellular respiration.
DOK 1
Bandaging Bacteria
Some bacteria are harmful, such as Staphylococcus and Pseudomonas. These bacteria release toxins that burst open human cells. They rob the cell of glucose, which they use for energy. This allows the bacteria to reproduce very quickly and go on to attack more human cells. Some bacteria are helpful, such as E. coli. These bacteria are important to human bodies because they produce vitamin K. They also help protect human cells by blocking the growth of disease-causing bacteria. Chemical compounds called antibiotics are used to destroy harmful types of bacteria. However, these antibiotics can also destroy useful bacteria such as E. coli, which is used to make one type of vitamin K. Vitamin K is needed to clot blood.
Scientists are working to develop a new kind of bandage that helps fight infections caused by harmful bacteria. The bandage material contains tiny capsules that look like human cells. Inside the capsules are antibiotics. When capsules in the bandage material are attacked by bacteria, they release antibiotics that destroy the bacteria on contact.
For his science project, Ben investigated the bandage material using three different types of bacteria. He followed these steps:
1) Filled four Petri dishes with nutrient gel and labeled them 1 through 4
2) Placed a swab in the Staphylococcus bacteria and rubbed the swab onto Petri dish 1, placing the lid on tightly
3) Used the same swab to repeat step 2 with Pseudomonas in Petri dish 2, placing the lid on tightly
Mississippi Department of Education Office of Student Assessment
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4) Used the same swab to repeat step 2 with E. coli in Petri dish 3, placing the lid on tightly
5) Did not place any bacteria in Petri dish 4, placing the lid on tightly
6) Placed all of the Petri dishes on a shelf, away from light and moisture for 24 hours
7) Placed equal amounts of the bandage material in each Petri dish
8) Placed all of the Petri dishes on a shelf, away from light and moisture for 36 hours
9) Repeated steps 1 through 8 for a total of three trials
The following table shows the results of the investigation.
Effects of Bandage Material on Bacterial Growth
PetriDish
Bacteria Added Description of Results after 36 Hours
1
2
3
4
Staphylococcus
Pseudomonas
E. Coli
None No bacteria present
Most bacteria destroyed Only small amount of bacteria remain
Most bacteria destroyed Only small amount of bacteria remain
Most bacteria destroyed Only small amount of bacteria remain
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43. What are the reactants and the products of cellular respiration in the harmful
bacteria? A. Reactants: oxygen, glucose from human cells
Products: water, carbon dioxide, energy B. Reactants: glucose, water from human cells
Products: oxygen, energy, carbon dioxide C. Reactants: energy from human cells, nitrogen
Products: glucose, water, oxygen D. Reactants: nitrogen, glucose from human cells
Products: water, oxygen, carbon dioxide
A is the correct answer.
During cellular respiration, the cell uses oxygen and glucose to produce
energy. The waste products, carbon dioxide and water, are also obtained
through this process.
B is not the correct answer.
During cellular respiration, cells use oxygen to break down glucose and
produce energy, carbon dioxide, and water. This response switches water
and oxygen in the reactants and products.
C is not the correct answer.
During cellular respiration, cells use oxygen to break down glucose and
produce energy, carbon dioxide, and water. Nitrogen is not involved in this
process.
D is not the correct answer.
During cellular respiration, cells use oxygen to break down glucose and
produce energy, carbon dioxide, and water. Nitrogen is not involved in this
process.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 72 of 98
Grade 8
Strand Earth and Space Science
Competency 4: Describe the Earth’s System in terms of its position to objects in the
universe, structure and composition, climate, and renewable and
nonrenewable resources.
PLD 4 a Proficient: Compare and contrast the lithosphere and the asthenosphere.
DOK 1
44. Which of these describes the lithosphere and the asthenosphere? F. The lithosphere is rigid and immovable, and the asthenosphere is hot and flowing. G. The asthenosphere is rigid and immovable, and the lithosphere is hot and flowing. H. Both are hot inner layers of earth capable of bending and moving. J. Both are hard and rigid layers of earth close to the surface.
F is the correct answer.
The lithosphere is brittle and rigid and does not move freely. If internal
Earth forces cause motion, the lithospheric plates will rub, collide, or
diverge. The asthenosphere is much hotter than the lithosphere, allowing
the rock in the asthenosphere to flow and change shape easily.
G is not the correct answer.
The asthenosphere is hot and flowing, and the lithosphere is rigid and
immovable.
H is not the correct answer.
The lithosphere and the asthenosphere are located in the upper layer of
Earth, not the inner layers. The asthenosphere is able to bend and move,
but the lithosphere is rigid and does not move easily.
J is not the correct answer.
The lithosphere and the asthenosphere are located in the upper layer of
Earth, but only the lithosphere is rigid. The asthenosphere is plastic and
flowing.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 73 of 98
Grade 8
Strand Earth and Space Science
Competency 4: Describe the Earth’s System in terms of its position to objects in the
universe, structure and composition, climate, and renewable and
nonrenewable resources.
PLD 4 a Advanced: Explain how the composition of the lithosphere and
asthenosphere affects plate movement.
DOK 2
45. Which of these describes a cause of lithospheric plate movement across the
surface of Earth? A. The plates are driven by bubbles from the boiling liquid of the asthenosphere. B. The plates float on dense liquid material of the asthenosphere and are moved by tidal
forces. C. The plates are driven across the surface by convection currents within the plastic
rock of the asthenosphere. D. The plates move because they are attached to the solid rock of the asthenosphere
and move with that rock.
C is the correct answer.
The asthenosphere is composed of rock that is partially melted. This
causes the asthenosphere to take on plastic-like properties. The
asthenosphere is not as hot as the lower mantle below it, so uneven
heating occurs, causing warmer areas within the asthenosphere to rise and
cooler areas to sink. This creates convection currents that cause plate
movement.
A is not the correct answer.
The asthenosphere is part of the upper mantle, which is not as hot as the
lower mantle. Thus, uneven heating causes rising of warmer areas and
sinking of cooler areas, producing convection currents. These currents are
similar to the effect of boiling. However, the asthenosphere is not boiling
because it is only partially liquefied.
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MST2 Grade 8 Practice Test 4 - Annotated Page 74 of 98
B is not the correct answer.
The asthenosphere is not completely liquefied. Rather, it is plastic-like and
flowing. The uneven heating of this plastic, flowing layer creates convection
currents, rather than tidal forces, that cause lithospheric plate movement.
D is not the correct answer.
The asthenosphere is not a solid rock. It is a plastic-like, flowing layer on
which the solid lithospheric plates float but are not attached. Convection
currents within the asthenosphere cause plate movement.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 75 of 98
Grade 8
Strand Earth and Space Science
Competency 4: Describe the Earth’s System in terms of its position to objects in the
universe, structure and composition, climate, and renewable and
nonrenewable resources.
PLD 4 a Basic: Identify the composition, physical nature, or location of the
lithosphere or the asthenosphere.
DOK 1
46. Which of these describes the lithosphere? F. Topmost solid part of Earth in which crust is located G. Middle liquid, flowing layer of Earth on which crust floats H. Middle plastic, flowing layer of Earth on which the asthenosphere floats J. Topmost semisolid part of Earth in which magma chambers for volcanoes form
F is the correct answer.
This response describes the lithosphere accurately as consisting of the
rigid, topmost part of the mantle and all of the crust.
G is not the correct answer.
This is a description of the asthenosphere, which is the hot, plastic-like
layer just under the lithosphere and is still part of the upper mantle.
H is not the correct answer.
This is a combination of the definitions of the lithosphere and the
asthenosphere. The lithosphere floats on the asthenosphere, but the
asthenosphere is the middle, plastic, flowing layer.
J is not the correct answer.
Magma chambers may be located in the lithosphere, but this layer is
completely solid and rigid.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 76 of 98
Grade 8
Strand Earth and Space Science
Competency 4: Describe the Earth’s System in terms of its position to objects in the
universe, structure and composition, climate, and renewable and
nonrenewable resources.
PLD 4 b Proficient: Describe the cause and effect relationship between the
composition of and movement within the Earth’s lithosphere.
DOK 1
47. About 30 miles into Earth, the speed of seismic waves increases.
What does this change in speed indicate about the material through which the seismic waves are traveling?
A. The waves travel from rock into metal material. B. The waves travel from cool material into hot material. C. The waves travel from solid material into liquid material. D. The waves travel from a less dense material into a more dense material.
D is the correct answer.
The factor that has the greatest influence over seismic wave speed in the
lithosphere is the composition of the material through which it is traveling.
Since waves travel faster in more dense materials, they must be traveling
from less to more dense material in this situation.
A is not the correct answer.
The lithosphere is not composed of metal. Rather, it is the rigid top layer of
Earth, composed of cool rock.
B is not the correct answer.
The factor that has the greatest influence over seismic wave speed in the
lithosphere is the composition of the material through which it is traveling.
Additionally, it is not likely that the waves are traveling from cool to hot
material because the lithosphere is composed of cooled rock at the surface
of Earth.
C is not the correct answer.
The lithosphere is composed of solid, rigid rock. Since it is the cool, upper
layer of Earth, there is no liquid material present here.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 77 of 98
Grade 8
Strand Earth and Space Science
Competency 4: Describe the Earth’s System in terms of its position to objects in the
universe, structure and composition, climate, and renewable and
nonrenewable resources.
PLD 4 b Advanced: Predict geologic phenomena based on the composition and
movement of interacting plates.
DOK 3
48. The following diagram shows the motion of two plates.
Which of these explains the feature that can form at the boundary of these two
plates? F. A broad canyon-like valley because the two colliding plates act like a plow, digging out
any soil in the plates’ paths. G. Volcanic mountain range because one oceanic plate melts underneath the continental
plate, forming composite volcanoes on the continent H. Island arc because one oceanic plate melts underneath the continental plate, forming
volcanic mountains that eventually become islands J. Folded mountain range because the two colliding plates have equal composition and
density, causing both to fold and form wide, thick mountains.
ContinentalCrust
OceanicCrust
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G is the correct answer.
Oceanic plates are more dense than continental plates. The more dense
oceanic plate will subduct under the less dense continental plate. The
mantle above the subducting plate melts and is pushed up toward the
surface of Earth, forming volcanic mountains.
F is not the correct answer.
The collision of the plates occurs at a boundary below the crust and cannot
be seen from the surface of Earth.
H is not the correct answer.
The collision of two oceanic plates creates an island arc. The collision
between an oceanic plate and a continental plate leads to volcano
formation on the continental crust rather than the oceanic crust because
the more dense oceanic plate subducts under the less dense continental
plate.
J is not the correct answer.
Oceanic plates are more dense than continental plates. The more dense
oceanic plate will subduct, rather than fold, under the less dense
continental plate, forming volcanic mountains.
Mississippi Department of Education Office of Student Assessment
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Grade 8
Strand Earth and Space Science
Competency 4: Describe the Earth’s System in terms of its position to objects in the
universe, structure and composition, climate, and renewable and
nonrenewable resources.
PLD 4 b Basic: Identify plate boundaries based on lithospheric movement.
DOK 1
49. Which of these describes a divergent boundary? A. Two continental plates moving away from each other, forming a rift valley B. Two oceanic plates rubbing against each other, forming a midocean ridge C. Two continental plates colliding, forming a mountain range D. Two oceanic plates colliding, forming a volcanic arc
A is the correct answer.
A divergent boundary is established where two plates are moving away
from each other. When this happens on land between two continental
plates, a rift valley forms.
B is not the correct answer.
A divergent boundary between two oceanic plates would result in a mid-
ocean ridge. This answer response refers to plates that are rubbing against
each other, and that would instead establish a transform boundary.
C is not the correct answer.
A divergent boundary between two continental plates would result in a rift
valley, not a mountain range. This response refers to plates that are
colliding, which would instead establish a convergent boundary.
D is not the correct answer.
A divergent boundary between two oceanic plates would result in a mid-
ocean ridge, not a volcanic arc. This response refers to plates that are
colliding, which would instead establish a convergent boundary.
Mississippi Department of Education Office of Student Assessment
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Grade 8
Strand Earth and Space Science
Competency 4: Describe the Earth’s System in terms of its position to objects in the
universe, structure and composition, climate, and renewable and
nonrenewable resources.
PLD 4 c Proficient: Examine weather forecasting and describe how meteorologists
use atmospheric features and technology to predict the weather.
DOK 2
50. Early in the afternoon, a weather station outside the school shows that the
barometric pressure and temperature are both dropping rapidly. What type of weather do these readings indicate?
F. Several days of clear, sunny weather G. Cool, cloudy weather with little chance of rain H. Thunderstorms later in the afternoon or evening J. Clearing weather today with rain likely tomorrow
H is the correct answer.
Rapidly dropping temperature and pressure are indications that a front is
quickly approaching, bringing heavy rain and thunderstorms.
F is not the correct answer.
Clear, sunny weather would be expected after a cold front has passed and
during the presence of a high-pressure system. Rapidly dropping
temperature and pressure indicate that the front is approaching and has not
yet passed.
G is not the correct answer.
Cool, cloudy weather with little chance of rain would be expected as a cold
front passes through an area with warm, dry weather. Because the
temperature and pressure are rapidly decreasing, a cold front is most likely
approaching an area with warm, moist air, bringing heavy rain and
thunderstorms.
J is not the correct answer.
Rapidly dropping temperature and pressure are an indication that a front is
quickly approaching. This would lead to rain and thunderstorms, followed
by clearing weather the next day.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 81 of 98
Grade 8
Strand Earth and Space Science
Competency 4: Describe the Earth’s System in terms of its position to objects in the
universe, structure and composition, climate, and renewable and
nonrenewable resources.
PLD 4 c Advanced: Predict a change in weather based on differences in pressure,
heat, air movement, and humidity.
DOK 3
51. A meteorologist is monitoring the weather around Capital City. She collects the
following data from her weather instruments: • Air pressure dropping quickly • Warm air rising rapidly • Water droplets being pushed upward to the topmost part of a cumulonimbus
cloud • Doppler radar map shows pockets of air with the wind blowing in opposite
directions Based on the weather data, what should the meteorologist include in the weather forecast for the Capital City area?
A. Increasing humidity with light rain B. Drop in air temperature with light snow C. Tornado watch with heavy rain and hail D. Approaching hurricane with heavy rain and strong winds
C is the correct answer.
The data collected indicate that the conditions are right for a severe
thunderstorm with the potential to create tornadoes. Air pressure dropping
quickly and warm air rising indicate that a cold front is quickly approaching
and forcing the warm, moist air at the surface to rise. The presence of a
cumulonimbus cloud and water droplets being pushed upward are signs of
a strong updraft that could cause tilt and rotation. Wind blowing in opposite
directions on the radar map also indicates wind shear and the possibility for
rotation within the thunderstorm, which could lead to a tornado.
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A is not the correct answer.
The data collected indicate that the conditions are right for a severe
thunderstorm with the potential to create tornadoes. This is the result of a
cold front approaching an area of warm, moist air. Increasing humidity and
light rain would be indicated by a warm front approaching rather than a cold
front.
B is not the correct answer.
The data collected indicate that the conditions are right for a severe
thunderstorm with the potential to create tornadoes. This is the result of a
cold front approaching an area of warm, moist air. Light snow would be
indicated by a warm front approaching and air temperatures below freezing
throughout the atmosphere. The presence of warm air rising rapidly
indicates that this is not what is happening.
D is not the correct answer.
The data collected indicate that a quick-moving system is approaching. The
rapidly rising warm air and wind blowing in opposite directions mean that
the system is forming. An approaching hurricane would create strong winds
and heavy rains, like a thunderstorm, but development would not occur
over land because hurricanes develop over warm ocean water.
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Grade 8
Strand Earth and Space Science
Competency 4: Describe the Earth’s System in terms of its position to objects in the
universe, structure and composition, climate, and renewable and
nonrenewable resources.
PLD 4 d Proficient: Research the importance of the conservation of renewable and
nonrenewable resources, including Mississippi, and justify
methods that might be useful in decreasing the human impact
on global warming.
DOK 3
52. Deforestation is the removal of naturally occurring forests. These forests are
cleared in order to provide land for farms or buildings. Some scientists want to reduce the amount of deforestation. How would reducing deforestation affect global warming?
F. It would prevent farmers from planting renewable biofuels that would have reduced
global warming. G. It would decrease the amount of carbon dioxide reaching the atmosphere, reducing
global warming.
H. It would increase the amount of oxygen released into the atmosphere, which would
bond together and create ozone, increasing global warming. J. It would prevent destruction of animal homes, allowing these animals to survive and
breathe in oxygen that would otherwise increase global warming.
G is the correct answer.
Reducing deforestation would decrease the amount of carbon dioxide in
the atmosphere because fewer trees would be cut down, and trees use
carbon dioxide during photosynthesis. Reduction in the amount of carbon
dioxide in the atmosphere decreases global warming.
F is not the correct answer.
Since trees use carbon dioxide during photosynthesis, reducing
deforestation would likely decrease the amount of carbon dioxide in the
atmosphere and decrease global warming. Additionally, the information
given refers to using the land for farms and buildings, and the types of
farms are not indicated. Therefore, forests removed through deforestation
are not necessarily replaced by renewable biofuels.
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H is not the correct answer.
A decrease in the amount of carbon dioxide due to a decrease in
deforestation would actually lead to a decrease in global warming.
Increasing the amount of oxygen in the atmosphere and the creation of
ozone would not increase global warming.
J is not the correct answer.
A decrease in carbon dioxide in the atmosphere because of an increase in
the number of trees using it during photosynthesis would cause a decrease
in global warming. Reducing deforestation could prevent destruction of
animal homes, which would benefit the environment but does not affect
global warming.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 85 of 98
Grade 8
Strand Earth and Space Science
Competency 4: Describe the Earth’s System in terms of its position to objects in the
universe, structure and composition, climate, and renewable and
nonrenewable resources.
PLD 4 d Basic: Identify renewable or nonrenewable resources.
DOK 1
53. Which of these is a renewable energy resource that does not produce carbon
dioxide? A. Coal B. Wind C. Biomass D. Fossil fuel
B is the correct answer.
Wind is a renewable resource because it can be used to produce energy
over and over again. The use of wind as an energy source does not involve
burning, so it does not produce carbon dioxide.
A is not the correct answer.
Coal is a nonrenewable resource because it exists in limited amounts on
Earth. It takes millions of years for decayed plants to turn into coal. As it
burns, coal produces carbon dioxide.
C is not the correct answer.
Biomass is renewable but produces carbon dioxide as it burns.
D is not the correct answer.
Fossil fuels are nonrenewable resources because they exist in limited
amounts on Earth. Burning of fossil fuels produces carbon dioxide.
Mississippi Department of Education Office of Student Assessment
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Grade 8
Strand Earth and Space Science
Competency 4: Describe the Earth’s System in terms of its position to objects in the
universe, structure and composition, climate, and renewable and
nonrenewable resources.
PLD 4 e Proficient: Explain how the tilt of Earth’s axis and the position of the Earth
in relation to the sun determine climatic zones, season, and
length of the days.
DOK 2
54. At a certain time of year, the Southern Hemisphere is tilted toward the sun.
Which of these describes how this tilt affects the Southern Hemisphere during this time of year?
F. The days will be longer in the Southern Hemisphere during this time of year. G. The nights will be longer in the Southern Hemisphere during this time of year.
H. The seasons will be longer in the Southern Hemisphere during this time of year. J. The sun will rise lower in the sky in the Southern Hemisphere during this time of year.
F is the correct answer.
The hemisphere of Earth that is tilted toward the sun receives more direct
sunlight and experiences the summer season. During the summer season,
the summer solstice occurs, which is the day that the sun reaches the
highest point in the sky and is the longest day of the year for that
hemisphere. Thus, the days are longer for the Southern Hemisphere when
it is tilted toward the sun.
G is not the correct answer.
The nights will be longer in the Southern Hemisphere during the winter.
This corresponds to the summer for the Northern Hemisphere. During its
winter season, the Southern Hemisphere is tilted away from the sun rather
than toward the sun.
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H is not the correct answer.
During the time of year when the Southern Hemisphere is tilted toward the
sun, this hemisphere will experience summer and longer days. The
seasons occur because of the tilt of Earth, but the length of seasons is not
changed.
J is not the correct answer.
The hemisphere of Earth that is tilted toward the sun receives more direct
sunlight and experiences longer days. During the summer season, the days
are longer because the sun reaches the highest point in the sky on the
summer solstice.
Mississippi Department of Education Office of Student Assessment
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Grade 8
Strand Earth and Space Science
Competency 4: Describe the Earth’s System in terms of its position to objects in the
universe, structure and composition, climate, and renewable and
nonrenewable resources.
PLD 4 e Advanced: Explain how a change in the angle of Earth’s axis affects climate
and seasons.
DOK 3
55. The following diagrams show the axis of Earth at its present 23° angle and at a
perpendicular axis of 0°.
How would seasons be affected if Earth’s axis were at a 0° angle? A. Earth would have no seasons. B. Seasonal variation would decrease at the poles. C. Seasonal variation would increase at the equator. D. Earth would have two seasons instead of four seasons.
A is the correct answer.
The tilt of Earth’s axis is what causes the seasons on Earth. If the tilt were
0°, Earth would not be tilted and no seasons would occur.
B is not the correct answer.
Seasonal variation would decrease at the poles because the poles would
no longer be angled toward or away from the sun. Indirect sunlight would
be equally distributed at each pole.
C is not the correct answer.
Seasonal variation would decrease at the equator because the equator
would no longer be angled toward or away from the sun. Direct sunlight
would be equally distributed at each pole.
D is not the correct answer.
The tilt of Earth’s axis is what causes the seasons on Earth. If the tilt were
0°, all parts of Earth would receive the same amount of sunlight during all
parts of the year. Earth would not experience any seasonal variation.
Earth with Axisat 23º Angle
Earth with Axisat 0º Angle
Mississippi Department of Education Office of Student Assessment
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Grade 8
Strand Earth and Space Science
Competency 4: Describe the Earth’s System in terms of its position to objects in the
universe, structure and composition, climate, and renewable and
nonrenewable resources.
PLD 4 e Basic: Identify the effect of Earth’s tilt on its axis or the position of Earth in
relation to the Sun on seasons and climate.
DOK 1
56. During which season does sunlight strike the Northern Hemisphere as shown?
F. Spring G. Summer H. Fall J. Winter
G is the correct answer.
When Earth tilts on its axis so that the Northern Hemisphere is toward the
sun, the Northern Hemisphere experiences summer. It is the time of the
year when the Northern Hemisphere receives the greatest amount of direct
sunlight.
F is not the correct answer.
On the first day of spring in the Northern Hemisphere, Earth’s tilt is neither
toward nor away from the sun. Earth is at an equinox, meaning that the
Northern and Southern Hemispheres receive equal amounts of direct
sunlight on that day.
SunlightEarth
N
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H is not the correct answer.
On the first day of fall in the Northern Hemisphere, Earth’s tilt is neither
toward nor away from the sun. Earth is at an equinox, meaning that the
Northern and Southern Hemispheres receive equal amounts of direct
sunlight on that day.
J is not the correct answer.
When Earth tilts on its axis so that the Northern Hemisphere is away from
the Sun, the Northern Hemisphere experiences winter. It is the time of the
year when the Northern Hemisphere receives the least amount of direct
sunlight.
Mississippi Department of Education Office of Student Assessment
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Grade 8
Strand Earth and Space Science
Competency 4: Describe the Earth’s System in terms of its position to objects in the
universe, structure and composition, climate, and renewable and
nonrenewable resources.
PLD 4 f Proficient: Describe the hierarchical structure (stars, clusters, galaxies,
galactic clusters) of the universe and examine the expanding
universe to include its age and history and the modern
techniques used to measure objects and distances in the
universe.
DOK 2
57. Astronomers often try to find the hottest stars in our galaxy.
Which wavelength of radiation do astronomers use to detect these hottest stars?
A. Infrared B. Ultraviolet C. Visible D. X-ray
B is the correct answer.
Astronomers use detectors to study certain wavelengths of light. The
hottest stars in our galaxy emit mostly ultraviolet wavelengths of light.
Cooler stars emit most of their light in lower-energy regions of the
electromagnetic spectrum, rather than in the ultraviolet region. It is easiest
to spot hot stars using ultraviolet light because they emit the most light in
this region.
A is not the correct answer.
Astronomers use detectors to study certain wavelengths of light. Cooler,
lower-energy stars generally emit most light in the infrared part of the
spectrum. Since dust clouds in space do not absorb infrared wavelengths,
these are used to study cooler stars that have low energy and are hidden
by dust clouds.
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C is not the correct answer.
Visible wavelengths of light are emitted by most stars, regardless of
temperature. Therefore, using visible light would not help astronomers to
distinguish the hottest stars from cooler stars.
D is not the correct answer.
X-rays are not generally emitted by stars. Although hot stars emit some
energy in the x-ray region, they emit mostly ultraviolet light. Cosmic
explosions, such as supernovas and black holes, are generally studied
using x-ray radiation.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 93 of 98
Grade 8
Strand Earth and Space Science
Competency 4: Describe the Earth’s System in terms of its position to objects in the
universe, structure and composition, climate, and renewable and
nonrenewable resources.
PLD 4 f Advanced: Explain techniques used to determine distances between
objects in the universe or used to determine the age of the
universe.
DOK 3
58. What can scientists conclude about a galaxy whose light is shifted toward shorter
wavelengths? F. The galaxy is very distant and is moving away from Earth very rapidly. G. The galaxy is orbiting the center of the Milky Way at a very high speed.
H. The galaxy is expanding so rapidly that it appears to be moving toward Earth. J. The galaxy is relatively close since a distant galaxy's light is shifted toward longer
wavelengths.
J is the correct answer.
Each galaxy emits light that is displayed as visible colors on the
electromagnetic spectrum. A galaxy moving farther away from Earth has an
increase in electromagnetic wavelength. This longer wavelength is
displayed as a shift to the redder portion of the electromagnetic spectrum.
A galaxy that is closer to Earth has a shorter wavelength that has very little
red shift on the electromagnetic spectrum.
F is not the correct answer.
Distant galaxies emit light that is shifted toward longer wavelengths on the
electromagnetic spectrum. The speed at which a galaxy moves toward or
away from Earth is determined by how much the light is shifted. A shorter
wavelength demonstrates the galaxy is relatively close.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 94 of 98
G is not the correct answer.
A galaxy in the center of our Milky Way galaxy would emit light that is
shifted to the shorter-wavelength portion of the electromagnetic spectrum.
However, a galaxy is composed of billions of stars and therefore would not
orbit the center of another galaxy.
H is not the correct answer.
Because Earth is not the center of the universe, it is possible that a galaxy
is moving in an outward direction toward the Milky Way galaxy. However,
the galaxy in the question emits light that is shifted toward shorter
wavelengths of an electromagnetic spectrum. This indicates the galaxy is
close to Earth and therefore is moving at a constant rate similar to that of
the Milky Way galaxy and not expanding rapidly.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 95 of 98
Grade 8
Strand Earth and Space Science
Competency 4: Describe the Earth’s System in terms of its position to objects in the
universe, structure and composition, climate, and renewable and
nonrenewable resources.
PLD 4 g Proficient: Justify the importance of continued research and use of new
technology in the development and commercialization of
potentially useful natural products, including, but not limited to,
research efforts in Mississippi.
DOK 3
59. The raising of catfish is a major industry in Mississippi. Catfish farmers in
Mississippi want scientists to research diseases affecting catfish. The following list describes the farmers’ reasons for wanting catfish diseases researched: 1) Understanding catfish diseases may lead to preventing these diseases. 2) Researching catfish diseases may help prevent diseases in other fish. 3) Curing catfish diseases may allow catfish farmers to raise more, healthier fish. 4) Studying catfish diseases may create catfish medications that the farmers could
sell to earn a profit. Which reasons from the list are logical justifications for researching catfish diseases?
A. 1 and 4 only B. 2 and 3 only C. 1, 2, and 3 only D. 2, 3, and 4 only
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 96 of 98
C is the correct answer.
Statements 1, 2, and 3 all provide logical justifications for researching
disease. Prevention of disease in catfish as well as other fish and raising
healthier fish will have positive effects on the catfish industry in Mississippi.
A is not the correct answer.
Statement 1 provides logical justification for continuing this research, but
statement 4 does not. Preventing disease will have a positive effect on the
catfish industry. However, the profit earned by selling catfish medication will
directly benefit only the individual farmers who are selling the product rather
than the entire industry.
B is not the correct answer.
Statements 2 and 3 both provide logical justification for continuing this
research, but statement 1 also provides a logical justification. Prevention of
disease in catfish as well as other fish and raising healthier fish will have
positive effects on the catfish industry in Mississippi.
D is not the correct answer.
Statements 2 and 3 both provide logical justification for continuing this
research, but statement 4 does not. Prevention of disease in catfish as well
as other fish and raising healthier fish will have positive effects on the
catfish industry in Mississippi. However, the profit earned by selling catfish
medication will directly benefit only the individual farmers who are selling
the product rather than the entire industry.
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 97 of 98
Grade 8
Strand Earth and Space Science
Competency 4: Describe the Earth’s System in terms of its position to objects in the
universe, structure and composition, climate, and renewable and
nonrenewable resources.
PLD 4 h Proficient: Justify why an imaginary hurricane might or might not hit a
particular area, using important technological resources.
DOK 2
60. The following map shows the location of a hurricane in the Gulf of Mexico at 81° W
and 17° N.
Which of these describes the likely outcome for this hurricane?
F. The rotation of Earth will force the hurricane to the southeast, where it will make landfall.
G. The dry land surrounding the hurricane will absorb moisture from the hurricane, causing it to break apart.
H. Strong trade winds will blow the hurricane across the Yucatan Peninsula toward Mexico, where it will make landfall.
J. Strong ocean currents moving from the equator to the north will push the hurricane into Cuba, where it will break apart into many smaller storms.
Hurricane in the Gulf of Mexico
5 hurricane
5 high pressure
Key
1008 W 958 W 908 W 858 W 808 W 758 W
108 N
158 N
208 N
258 N
308 N
358 N
Gulfof
Mexico
MexicoYucatan
Peninsula
Cuba
N
S
EW
H
H
Mississippi Department of Education Office of Student Assessment
MST2 Grade 8 Practice Test 4 - Annotated Page 98 of 98
H is the correct answer.
The trade winds between the equator and 30°N latitude blow from east to
west. These winds are the most influential factor in hurricane movement at
these latitudes. Since the hurricane is at 17°N latitude, the trade winds will
force it to move toward the Yucatan Peninsula, which is to the west.
F is not the correct answer.
Global winds are the most influential factor in guiding hurricane movement.
The rotation of Earth will not force the hurricane to move in a path opposite
to the prevailing winds at this latitude.
G is not the correct answer.
The hurricane has not yet made landfall and is still able to absorb moisture
from the warm ocean surrounding it. It will first be influenced by the trade
winds blowing east to west and will then make landfall and break apart as it
moves across the Yucatan Peninsula.
J is not the correct answer.
Global winds are the most influential factor in guiding hurricane movement.
Even though ocean currents may move toward the northeast, the prevailing
winds at this latitude will push the hurricane to the west, toward the
Yucatan Peninsula.