2007 Science OGT Answer Key
1.) A
In this question, students need to determine how the properties of two liquids differ, based on pictures. The
Ohio Academic Content Standards for OGT Science state that students will describe the identifiable physical
properties of substances.
2.) A
In this question, students need to identify which trait of the European rabbit enabled it to quickly become a
major pest in Australia. The Ohio Academic Content Standards for OGT Science state that students must
understand how ecosystems change over time.
3.) B
In this question, students need to identify which human activity may increase the myxoma virus’s impact on the
current rabbit population. The Ohio Academic Content Standards for OGT Science state that students will
understand how human activities can impact the status of natural systems.
4.) C
In this question, students need to identify why traits of certain rabbits became more common in the rabbit
population as a result of natural selection. The Ohio Academic Content Standards for OGT Science state that
students must know that evolutionary relationships contribute to the diversity of life.
5.) D
In this question, students need to understand the relationships between species, as represented through a
biological classification system. The Ohio Academic Content Standards for OGT Science state that students
must understand how evolutionary relationships contribute to an understanding of the unity and diversity of life.
6.) B
In this question, students need to identify which climatograph best represents the annual temperature and
precipitation of a tropical rainforest. The Ohio Academic Content Standards for OGT Science state that students
will explain climate patterns within Earth’s systems.
See Scoring Guidelines for This Question
Points
Student Response
The student response describes the difference between the covalent bond in Cl2 and the ionic bond in
NaCl in terms of electrons.
OR
2
The student response may provide two correctly labeled drawings (e.g., Lewis Dot diagrams, Bohr
model, etc.)
OR
The student response may provide one correctly labeled drawing (e.g., Lewis Dot diagrams, Bohr model,
etc.) of the covalent bond in Cl2 or the ionic bond in NaCl and a description of the bond not illustrated in
the drawing.
The student response describes the covalent bond in Cl2 OR the ionic bond in NaCl.
OR
1
The student response may provide one correctly labeled drawing of either the covalent bond in Cl2 OR
the ionic bond in NaCl in terms of electrons.
OR
0
The student response may provide two partially correct drawings, but they may contain errors (e.g.,
some labels may be missing).
The student response indicates inadequate or no understanding of the task. The response may provide
incorrect or irrelevant information.
Explanation of Correct Answer
In covalent bonding the electrons (the negative particles outside the nucleus of an atom) are shared between
atoms (the basic building block of all matter). In the case of the chlorine (Cl) molecule (a compound made of
more than one atom) the electrons are shared between two chlorine atoms. In an ionic bond electrons are
transferred from one atom to another. In NaCl one valence electron (the electron the farthest from the nucleus)
is transferred from sodium to the chlorine atom.
In this question, students need to describe the difference between the formation of the covalent bond in Cl2 and
the ionic bond in NaCl. The Ohio Academic Content Standards for OGT Science state that students will explain
how atoms react with each other to form other substances.
7.) Answer is above.
8.) B
In this question, students need to determine why different amounts of water condensed on the outside of two
glasses. The Ohio Academic Content Standards for OGT Science state that students will describe the
identifiable physical properties of substances.
9.) A
In this question, students need to predict the relative size of a puddle formed by a Styrofoam® cup, compared
with glass and plastic. The Ohio Academic Content Standards for OGT Science state that students will describe
identifiable physical properties of substances.
10.)
C
In this question, students need to explain the development of the model of an acid. The Ohio Academic Content
Standards for OGT Science state that students will trace the historical development of scientific theories and
ideas.
17.)
D
In this question, students need to determine ethical obligations and guidelines that a research group is required
to observe during a scientific study. The Ohio Academic Content Standards for OGT Science state that students
will describe the ethical practices and guidelines in which science operates.
18.)
C
In this question, students need to determine why Copernicus’ heliocentric (sun centered) model of the solar
system replaced Ptolemy’s geocentric (earth centered) model of the solar system. The Ohio Academic Content
Standards for OGT Science state that students will summarize the historical development of scientific theories
and ideas in Earth and space sciences.
See Scoring Guidelines for This Question
Points
4
3
Student Response
The response demonstrates a complete understanding of the task by identifying two negative
consequences of increased animal waste in lakes and waterways and describing how the increased waste
results in each consequence.
The response demonstrates an understanding of the task by identifying two negative consequences of
increased animal waste in lakes and waterways and describing how the increased waste results in one
consequence.
Points
Student Response
OR
The response identifies one negative consequence of increased animal waste in lakes and waterways,
describes how the increased waste results in the consequence and provides another description without
identifying a consequence (e.g., “bacteria from the waste gets into the water”).
The response demonstrates a partial understanding of the task by identifying two negative consequences
of increased animal waste in lakes and waterways.
OR
2
The response identifies one negative consequence of increased animal waste in lakes and waterways and
describes how the increased waste results in the consequence.
OR
The response provides two descriptions of negative consequences without actually identifying those
consequences. The response is relevant to the task, but there may be gaps in focus.
The response identifies one negative consequence of increased animal waste in lakes and waterways.
OR
1
0
The response describes a negative consequence without actually identifying that consequence. The
response fails to identify or omits significant aspects of the task and may provide unrelated or unclear
information. There is little evidence of focus.
The response does not meet the criteria required to earn one point. The response indicates inadequate or
no understanding of the task. It may only repeat information from the passage or prompt without any
supporting information responsive to the task. The student may have written on a different topic or
written, “I don’t know.”
Explanation of Correct Answer
There are many consequences of increasing animal waste in lakes and waterways, which students can cite to
answer this question correctly. Excess nutrients from the waste would increase algae blooms, shade underwater
plants, reduce oxygen in the water, and eventually cause a large number of fish kills. Fish kills may also be
caused by increased turbidity (more materials floating in water) clogging fish gills and interfering with filter
feeders of the water system. Another correct answer would be that recreational use of waterways could be
restricted because of the excessive waste that would reduce swimmer visibility and possibly cause disease.
Other students might say that a loss of income could occur as a result of livestock deaths from drinking polluted
water, farmers having to purchase safe water, or loss of tourism.
In this question, students need to identify and describe two consequences of increased animal waste in lakes and
waterways. The Ohio Academic Content Standards for OGT Science state that students will understand how
human activities can conserve or deplete Earth’s resources.
19.)
Answer is above.
20.)
D
In this question, students need to identify which changes occur in a hot pack during a demonstration. The Ohio
Academic Content Standards for OGT Science state that students will understand how molecules react with
each other to form different substances.
21.)
B
In this question, students need to determine when a circuit will stop conducting electricity. The Ohio Academic
Content Standards for OGT Science state that students will explain how energy may change form or be
redistributed.
22.)
C
In this question students need to determine why electrons in a wire cannot flow into a hot pack. The Ohio
Academic Content Standards for OGT Science state that students will describe the identifiable physical
properties of substances.
23.)
C
In this question, students need to identify one change that would cause a motor to spin more slowly. The Ohio
Academic Content Standards for OGT Science state that students will explain the movement of objects by
applying Newton’s three laws of motion.
24.)
B
In this question, students need to determine the characteristic that describes the Arctic tundra based on the
annual temperature and precipitation for this area. The Ohio Academic Content Standards for OGT Science
state that students will understand patterns within Earth’s systems.
See Scoring Guidelines for This Question
Points
2
1
0
Student Response
The student response demonstrates a complete understanding of the task by identifying a condition
within the pond that could affect oxygen concentration values and by explaining its effect.
The student response demonstrates a partial understanding of the task by identifying a condition within
the pond that could affect oxygen concentration values but fails to correctly explain its effect.
The student response demonstrates no understanding of the task. The response may provide incorrect
information or be irrelevant to the task.
Explanation of Correct Answer
Less photosynthesis in the pond would mean that less oxygen was being produced. This can be caused by:




Large amount of plants and algae on the surface of the pond;
Low numbers of phytoplankton;
High populations of consumers of phytoplankton making the population lower;
High turbulence, causing more sediment to float in the water and more pollution in the pond.
In this question, students need to identify a condition in a pond that could result in a decrease in the oxygen
concentration and then explain why this condition decreases the oxygen concentration values. The Ohio
Academic Content Standards for OGT Science state that the student will understand how ecosystems change
over time.
25.)
Answer is above.
26.)
B
In this question, students need to identify the energy conversion that occurs during photosynthesis. The Ohio
Academic Content Standards for OGT Science state that students will explain the flow of energy through
biological and ecological systems.
27.)
C
In this question, students need to identify the process that would decrease the amount of dissolved oxygen in a
water sample. The Ohio Academic Content Standards for OGT Science state that students will understand the
cycling of matter through biological and ecological systems.
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Points
2
1
Student Response
The student response provides a scientific explanation for how computer modeling could be valuable to
an ecologist studying a forest ecosystem and speculates on why the computer program allows the
ecologist to gain data that could not otherwise be gained.
The student response provides a scientific explanation for how computer modeling could be valuable to
an ecologist.
OR
The student response speculates on why the computer program allows the ecologist to gain data that
Points
0
Student Response
could not otherwise be gained.
The student response indicates inadequate or no understanding of the task. The response may provide
incorrect or irrelevant information.
Explanation of Correct Answer
Computer models can help ecologists (people who study ecosystems) gain information about how a forest
ecosystem might be impacted by changes to the organisms (living things) within the ecosystem. This
information can best be obtained by using computer models, because changes, and the impact of changes, can
be immediately observed.
In this question, students need to explain the value of a computer program that predicts changes in ecosystems,
including the numbers of individuals within an ecosystem and their survival rates. Students also need to explain
how computer modeling is of value to an ecologist studying a forest ecosystem. The Ohio Academic Content
Standards for OGT Science state that students will explain that science and technology are interdependent.
28.)
Answer is above.
29.)
C
In this question, students need to understand which event of the 20th century influenced the recovery of the
white moth. The Ohio Academic Content Standards for OGT Science state that students will understand how
human activities can conserve or deplete Earth’s resources.
30.)
C
In this question, students need to interpret Kettlewell’s findings on peppered moths in industrialized areas
versus non-industrialized areas. The Ohio Academic Content Standards for OGT Science state that students will
explain the mechanisms and processes of biological evolution.
31.)
A
In this question, students need to identify what most likely caused the increase of black moths and decrease of
white moths between 1850 and 1900. The Ohio Academic Content Standards for OGT Science state that
students will understand that human activities can conserve or deplete Earth’s resources.
32.)
D
In this question, students need to determine the effect of using methane (CH4) from a coal mine to power fuel
cells instead of using gas. The Ohio Academic Content Standards for OGT Science state that students will
understand human activities that can conserve or deplete Earth’s resources.
See Scoring Guidelines for This Question
Points
4
3
Student Response
The response identifies two savings that result from recycling aluminum cans and explains an ecological
benefit of each.
The response identifies two savings that result from recycling aluminum cans and explains an ecological
benefit of one.
The response identifies two savings that result from recycling aluminum cans, but the explanations are
either absent or unclear (e.g., “If you recycled aluminum cans, you wouldn’t need as much aluminum for
new cans because you could use the recycled aluminum. Also, all those recycled cans would not be
going in the trash, so that is good for the environment.”).
2
OR
The response identifies one savings that results from recycling aluminum cans and explains an
ecological benefit.
The response identifies one savings that results from recycling aluminum cans but the explanation is
either absent or unclear.
1
0
OR
The response explains one ecological benefit.
The response indicates inadequate or no understanding of the task. The response may provide incorrect
or irrelevant information.
Explanation of Correct Answer
Energy required to acquire and produce raw materials (such as aluminum ore) would be saved. Ecosystems that
would be damaged by the acquisition (in this case, mining) of raw materials would be left undisturbed. Fossil
fuels required to produce raw materials would also be conserved.
In this question, students need to identify two savings that result from recycling aluminum cans and one
ecological benefit of each savings. The Ohio Academic Content Standards for OGT Science state that students
will describe how human activities can conserve or deplete Earth’s resources.
33.)
Answer is above.
34.)
D
In this question, the student needs to identify the negative consequences that might result from the introduction
of a bacterium gene from Bacillus thuringiensis (Bt), into the corn genome. The Ohio Academic Content
Standards for OGT Science state that students will explain that science and technology are interdependent.
35.)
A
In this question, students need to identify the geologic processes that caused the folding and faulting shown in
the cross-section image. The Ohio Academic Content Standards for OGT Science state that students will
explain the processes that move and shape Earth’s surface.
36.)
C
In this question, students need to determine which driver action would most likely cause a box in a car to appear
to slide to the west. The Ohio Academic Content Standards for OGT Science state that students will explain the
movement of objects by applying Newton’s three laws of motion.
See Scoring Guidelines for This Question
Points
2
Student Response
The student response explains that genetically similar mice would provide a control for the experiment,
allowing scientists to determine whether a mouse’s response to a drug was typical or if it was influenced
by genetic variations.
AND
The student response compares this with using mice that are not genetically similar (e.g., greater
diversity in DNA), which could result in a variation that inhibits or enhances the effects of the drug
being tested, making it difficult to determine the effectiveness of the drug.
The student response indicates that using mice that are genetically similar would provide a control for
the experiment, allowing scientists to determine whether a mouse’s response to a drug was typical or if it
was influenced by genetic variations, but the response fails to compare or incorrectly compares this with
using mice that are not genetically similar.
1
0
OR
The student response makes a comparison between using mice that are genetically similar and mice that
are not genetically similar, but the response is oversimplified or incomplete, (e.g., “mice that are similar
would react similarly, and mice that are different would react differently”).
The student response demonstrates no understanding of the task. The response may provide incorrect
Points
Student Response
information or be irrelevant to the task.
Explanation of Correct Answer
Using mice that are genetically similar would provide a control for the experiment and make it easier to identify
the effects of the drug. Using mice with a variety of genetic makeups would make it difficult to determine
whether the response was due to the drug or due to the difference in genetic makeup.
In this question, the student needs to explain the advantage of testing a new drug on mice that have been inbred
so that they all have nearly the same genetic makeup. The Ohio Academic Content Standards for OGT Science
state that students need to design, conduct, evaluate, and communicate the results of scientific investigations.
37.)
Answer is above.
38.)
C
In this question, students need to recall how similarities of rock layers on different continents led to Alfred
Wegener’s theory of continental drift. The Ohio Academic Content Standards for OGT Science state that
students will summarize the historical development of scientific theories and ideas in Earth and space sciences.
39.)
D
In this question, students need to identify which procedure would cause a Himalayan rabbit’s feet to grow white
hair. The Ohio Academic Content Standards for OGT Science state that students will design scientific
investigations.
40.)
B
In this question, students need to identify how a change in fur color would have a negative impact on
Himalayan rabbits in the wintertime. The Ohio Academic Content Standards for OGT Science state that
students will understand the structure and function of ecosystems.
41.)
D
In this question, students need to determine why fur color affects the warmth of a rabbit. The Ohio Academic
Content Standards for OGT Science state that students will demonstrate that waves transfer energy when they
interact with matter.
42.)
C
In this question, students need to identify the role that snowshoe hares play in the flow of energy through an
ecosystem. The Ohio Academic Content Standards for OGT Science state that students will describe how
energy flows through ecological systems.
43.)
B
In this question, students need to identify information that is assumed from data collected in a study. The Ohio
Academic Content Standards for OGT Science state that students must be able to evaluate the results of
scientific investigations.
44.)
C
In this question, students need to know what would prevent the lynx (predator) population from declining if the
hare (prey) population decreases. The Ohio Academic Content Standards for OGT Science state that students
will understand how ecosystems change over time.