answer key for the ny state lab test: making...
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Answer Key For The NY State Lab Test: Making Connections
Sm-Makingconnections
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Questions with Explanations For The Entire Test:
Sm-Makingconnections
Teacher Answer Key
**NO VERSION/RANDOM**
4 1. Base your answer on the information below and accompanying graph and on your
knowledge of biology.
Students were asked to design a lab that investigated the relationship between exercise
and heart rate. Heart rate was determined by recording the pulse rate in beats per minute.
The students hypothesized that increased exercise results in an increased heart rate. The
class results for the experiment are shown in the graph shown.
Students in a different science class carried out the same experiment. The data they
obtained did notsupport the hypothesis that increased exercise results in increased heart
rate. The most scientifically sound way to deal with this situation is to
1. write a new hypothesis 3. have the students in both classes vote to
decide which hypothesis is correct
2. read about pulse rate in a biology
textbook
4. ask students in a third class to do the
experiment and see if their results support
the hypothesis
4 The most scientifically sound way to deal with this situation is to ask students in a third
class to do the experiment and see if their results support the hypothesis. Repeatability of
experimental results is an essential component of sound science. If an experiment cannot
be repeated multiple times with the same results by independent researchers, it is likely
that the original experiment was flawed in some way and its results invalid.
WRONG CHOICES EXPLAINED (1), (3) It is not true that the most scientifically sound way to deal with this situation is
to write a new hypothesis or have the students in both classes vote to decide which
hypothesis is correct. Either of these actions would introduce bias into the experiment
and invalidate its results.
(2) It is not true that the most scientifically sound way to deal with this situation is
to read about pulse rate in a biology textbook. This is an action that should be taken by
the researcher as an initial part of the experimental method, not as an action to validate
experimental results.
4 2. Base your answer on the information below, on the accompanying data table, and on
your knowledge of biology.
A group of students obtained the following data while trying to determine the effect of
exercise on pulse rate.
Which statement is an example of an observation the students could have made?
1. Pulse rates in beats per minute decrease
for all people after exercise.
3. The pulse rate of student C was
dangerously low.
2. Student A most likely exercises regularly. 4. The pulse rate of student F increased by
30 beats per minute.
4 The pulse rate of student F increased by 30 beats per minute is the statement that is an
example of an observation the students could have made. This direct observation can be
made by examining the data from the table that indicate that the pulse rate of
person F before exercise was 68 beats per minute and after exercise was 98 beats per
minute, a difference of 30 beats per minute.
WRONG CHOICES EXPLAINED (1) Pulse rates in beats per minute decrease for all people after exercise is not the
statement that is an example of an observation the students could have made. No data are
provided in the table that indicate what happens to students' pulse rates after the
completion of exercise. So this observation cannot be made based on the data provided.
(2) Student A most likely exercises regularly is not the statement that is an example of an
observation the students could have made. No data are provided in the table that indicate
what exercise habits each subject maintains. So this observation cannot be made based on
the data provided.
(3) The pulse rate of student C was dangerously low is not the statement that is an
example of an observation the students could have made. No data are provided in the
table concerning the normal range of human pulse rate. So this observation cannot be
made based on the data provided.
1 3. A student hypothesized that watching sports on television would cause viewers' pulse
rates to increase. She designed an experiment to determine the effect of watching sports
on pulse rate. A group of 200 volunteers took their pulse rates and then watched their
favorite sports on television. After the games, they immediately took their pulse rates
again. The data collected showed that the pulse rates of some people increased, but the
pulse rates of an equal number of people did not change. Although the hypothesis was
not supported by the data, the hypothesis is still valuable because it
1. may lead to further investigation 3. is the opinion of the experimenter
2. can be changed to fit the data 4. is based on beliefs of the volunteers
1 Although the hypothesis was not supported by the data, the hypothesis is still valuable
because itmay lead to further investigation. Sound science uses situations such as
unsupported hypotheses as opportunities to conduct deeper or redirected research. Such
opportunities often result in information that can lead to the development of new
scientific theories.
WRONG CHOICES EXPLAINED (2), (3), (4) It is not true that although the hypothesis was not supported by the data, the
hypothesis is still valuable because it can be changed to fit the data, because it is the
opinion of the experimenter, or because it is based on beliefs of the volunteers. Any of
these actions would introduce bias into the experiment and invalidate its results. Sound
science requires that experimental hypotheses be tested against collected data and
analyzed objectively for accuracy. Hypotheses must not be manipulated to fit the data or
to support any particular opinion or belief.
3 4. Students were asked to determine if they could squeeze a clothespin more times in a
minute after resting than after exercising. An experiment that accurately tests this
question should include all of the following except
1. a hypothesis on which to base the design
of the experiment
3. two sets of clothespins, one that is easy to
open and one that is more difficult to open
2. a large number of students
4. a control group and an experimental
group with equal numbers of students of
approximately the same age
3 An experiment that accurately tests this question should include all of the following
except two sets of clothespins, one that is easy to open and one that is more difficult to
open. Using two sets of clothespins that differ in strength introduces an additional
variable to the experiment that will invalidate the results. Instead, all clothespins should
be the same strength in this experiment.
WRONG CHOICES EXPLAINED (1) An experiment that accurately tests this question should include a hypothesis on
which to base the design of the experiment. A good experiment always begins with a
hypothesis (an "educated guess") as to the researcher's prediction about its results.
(2) An experiment that accurately tests this question should include a large number of
students. A good experiment includes a significant number of experimental subjects as a
means of avoiding statistical bias in the experiment.
(4) An experiment that accurately tests this question should include a control group and
an experimental group with equal numbers of students of approximately the same age. A
good experiment always includes a control group that mirrors the experimental group in
all respects except the independent variable (controlled by the experimenter).
3 5. Base your answer on the information given and on your knowledge of biology.
In an investigation, 28 students in a class determined their pulse rates after performing
each of three different activities. Each activity was performed three times during equal
time intervals. The average results are shown in the accompanying graph.
Before constructing the graph it would have been most helpful to organize the results of
the investigation in
1. a research plan 3. a data table
2. an equation 4. a generalization
3 Before constructing the graph it would have been most helpful to organize the results
of the investigation in a data table. Data tables assist the researcher by providing a means
of organizing data during the course of an experiment. Properly designed, a data table
facilitates efficient analysis of experimental results.
WRONG CHOICES EXPLAINED (1) Before constructing the graph it would not have been most helpful to organize the
results of the investigation in a research plan. A research plan is an outline of the steps
that must be taken to run an experiment, collect and analyze data, and draw inferences
and conclusions. A research plan is drawn up well before data is collected and organized
into a data table.
(2) Before constructing the graph it would not have been most helpful to organize the
results of the investigation in an equation. An equation is a mathematical model that
assists scientists in describing a natural phenomenon and in better understanding it. An
equation is developed as an aspect of data analysis after data is collected.
(4) Before constructing the graph it would not have been most helpful to organize the
results of the investigation in a generalization. A generalization is a statement of
inference or conclusion that is developed as a result of considerable data collection,
analysis, and modeling. Generalizations are the last component of a research plan to be
developed.
1
6. Although the digestive system is primarily responsible for the breakdown of food, this
process can be disrupted if the circulatory system malfunctions because the nutrients
cannot be delivered to the cells that need them. The best explanation for this disruption is
that
1. Human body systems interact with each
other to perform life functions
3. the digestive system and the circulatory
system the same organs
2. the circulatory system is the control
center of the body
4. the circulatory system is responsible for
the the breakdown of food
1 The best explanation for this disruption is that human body systems interact with each
other to perform life functions. In humans, these systems are cooperative in their
operation and allow for coordination and homeostatic balance of the body.
WRONG CHOICES EXPLAINED (2), (4) The best explanation for this disruption is not that the circulatory system is the
control center of the body or that the circulatory system is responsible for the
coordination of life functions, including the breakdown of food. In humans, control and
coordination are functions provided by the nervous system, not the circulatory system.
(3) The best explanation for this disruption is not that the digestive system and the
circulatory system have many organs in common. In humans, these systems are separate
and distinct. They are cooperative in their operation and allow for coordination and
homeostatic balance of the body.
2 7. Base your answer on the accompanying information and on your knowledge of
biology.
An experiment was designed to test whether students could squeeze a clothespin more
times in one minute after resting or after exercise.
The dependent variable for this experiment is the
1. time the student was squeezing the
clothespin 3. strength of the student
2. number of times the student was able to
squeeze the clothespin 4. length of the clothespin
2 The dependent variable for this experiment is the number of times the student was able
to squeeze the clothespin. The dependent variable in an experiment is the factor that is
being measured and that changes in response to the experimental conditions controlled
by the researcher. In this case, the researcher is measuring the number of times the
students could squeeze a clothespin within a given time period (one minute) under two
different conditions (after rest or after exercise). In this experiment, the number of times
the clothespin is squeezed is the dependent variable.
WRONG CHOICES EXPLAINED: (1), (4) The dependent variable for this experiment is not the time the student was
squeezing the clothespin or the length of the clothespin. These factors represent constant,
not variable, conditions of the experiment. They are established by the researcher as a
part of the experimental method.
(3) The dependent variable for this experiment is not the strength of the student. Because
the student subjects tested in this experiment are individuals whose strength may vary
greatly, a large number of students should be tested to ensure that the experimental
results are not biased. This variable is neither dependent nor independent. It is an
experimental subject variable that should be factored into the experimental design.
3 8. In an experiment to test the effect of exercise on the number of times a clothespin can
be squeezed in 1 minute, the dependent variable would be the
1. test subject 3. number of squeezes
2. amount of exercise 4. clothespin
3 In an experiment to test the effect of exercise on the number of times a clothespin can
be squeezed in 1 minute, the dependent variable would be the number of squeezes. The
dependent variable in any experiment is the factor being tested, a factor that varies in
response to researcher-manipulated changes in the independent variable. In this case, the
number of squeezes in 1 minute is the variable dependent on the researcher-manipulated
variable, which is the amount of exercise done by the test subjects prior to the
experiment.
WRONG CHOICES EXPLAINED (1) In an experiment to test the effect of exercise on the number of times a clothespin can
be squeezed in 1 minute, the dependent variable would not be the test subject. The test
subject is the student whose responses to the independent variable are being tested and
recorded.
(2) In an experiment to test the effect of exercise on the number of times a clothespin can
be squeezed in 1 minute, the dependent variable would not be the amount of exercise.
The amount of exercise is the independent variable manipulated by the researcher.
(4) In an experiment to test the effect of exercise on the number of times a clothespin can
be squeezed in 1 minute, the dependent variable would not be the clothespin. The
clothespin is the equipment used to measure the dependent variable, not the variable
itself.
3 9. Base your answer on the accompanying diagram illustrating one type of cellular
communication and on your knowledge of biology.
If a stimulus is received by the cells at A, the cells at E will most likely use energy
obtained from a reaction between
1. DNA and RNA 3. glucose and oxygen
2. ecosystems and biospheres 4. populations and communities
3 The cells at E will most likely use energy obtained from a reaction between glucose
and oxygen if a stimulus is received by the cells at A. The diagram illustrates a reflex arc
involving a receptor organ (represented by the skin cells labeled A), a nerve connection
(represented by the nerve cells labeled B, C, and D), and an effector organ (represented
by the muscle cells labeled E). When a stimulus is received at A, the appropriate motor
response at E is typically muscle contraction. This motor response requires ATP energy
released during aerobic respiration involving a chemical reaction between oxygen and
glucose.
WRONG CHOICES EXPLAINED (1) The cells at E will not use energy obtained directly from a reaction between fats and
enzymes. Fats are complex foods that must be broken down (digested) into simpler
substances (fatty acids and glycerol) before they can be oxidized to release energy for
cell processes. Enzymes are organic catalysts that can speed up or slow down reactions,
including fat digestion, but do not react with other substances in these reactions.
(2) The cells at E will not use energy obtained directly from a reaction between ATP and
pathogens. ATP (adenosine triphosphate) is a chemical that temporarily stores energy for
cell processes. A pathogen is a disease-causing organism such as a virus or bacterium.
There is no known reaction that occurs between ATP and pathogens.
(4) The cells at E will not use energy obtained directly from a reaction between water
and carbon dioxide. Water and carbon dioxide are reactants in the biochemical process of
photosynthesis. Photosynthesis reactions store light energy in the chemical bonds of
glucose molecules. Although this reaction may ultimately result in the energy used at E,
it is not the most direct source of this energy.
4 10. Which organ system in humans is most directly involved in the transport of oxygen to
different tissues and cells in the body?
1. digestive 3. excretory
2. nervous 4. circulatory
4 The circulatory system in humans is most directly involved in the transport of oxygen.
Molecular oxygen is absorbed from the air into the moist lung tissues, where it diffuses
through capillary walls and into red blood cells. Red blood cells contain the protein
hemoglobin that links chemically with oxygen molecules. The absorbed oxygen is then
carried throughout the body within the circulatory system until it is released to tissues for
use in the process of cellular respiration.
WRONG CHOICES EXPLAINED (1) The digestive system in humans is not most directly involved in the transport of
oxygen. The digestive system is responsible for the breakdown and absorption of food
materials, not for carrying oxygen.
(2) The nervous system in humans is not most directly involved in the transport of
oxygen. The nervous system is responsible for regulating the body's activities by
receiving and interpreting environmental stimuli and by carrying nerve impulses from the
central nervous system to effectors such as muscles and glands.
(3) The excretory system in humans is not most directly involved in the transport of
oxygen. The excretory system is responsible for eliminating waste materials (e.g., carbon
dioxide, urea) from the body, not for carrying oxygen.
4 11. An experiment was designed to test whether students could squeeze a clothespin
more times in 1 minute after resting or after exercising. What would be a hypothesis for
the experiment?
1. Do students squeeze clothespins more
often in 1 minute after exercising?
3. Ten students who exercise before
squeezing a clothespin squeezed it more
times in 1 minute than ten students who
rested first.
2. Can most students squeeze a clothespin
more times after they rest?
4. Students who rest before squeezing a
clothespin will squeeze it fewer times in 1
minute than students who exercise
beforehand.
4 An hypothesis for this experiment would be students who rest before squeezing a
clothespin will squeeze it fewer times in 1 minute than students who exercise beforehand.
The hypothesis in an experiment is the researcher's best guess about the outcome of the
experiment. In this case, the researcher is measuring the number of times the students
could squeeze a clothespin within a given time period (1 minute) under two different
conditions (after rest or after exercise). This hypothesis projects that students who
exercise beforehand will be able to squeeze the clothespin more often than students who
do not.
WRONG CHOICES EXPLAINED (1), (2) A hypothesis for this experiment would not be do students squeeze clothespins
more often in 1 minute after exercising? or can most students squeeze a clothespin more
times after they rest?These are possible experimental questions that might be posed by
the researcher in preparation for setting up an experiment, not hypotheses.
(3) A hypothesis for this experiment would not be Ten students who exercised before
squeezing a clothespin squeezed it more times in 1 minute than ten students who rested
first. This is a possible observation that might be made by the researcher in analyzing and
representing the data collected during this experiment, not a hypothesis.
1 12. Which statement best describes a change that usually takes place in the human body
when the heart rate increases as a result of exercise?
1. More oxygen is delivered to muscle cells. 3. The rate of digestion increases.
2. Blood cells are excreted at a faster rate. 4. No hormones are produced.
1 More oxygen is delivered to muscle cells is the statement that best describes a change
that usually takes place in the human body when the heart rate increases as a result of
exercise. When the body exercises, muscle cells use oxygen in the process of cellular
respiration to release energy from glucose. In order to sustain activity, muscle tissue must
receive more oxygen and glucose, which is delivered to it by the bloodstream.
WRONG CHOICES EXPLAINED (2) Blood cells are excreted at a faster rate is not the statement that best describes a
change that usually takes place in the human body when the heart rate increases as a
result of exercise. The process of excretion is one in which toxic wastes such as carbon
dioxide and urea are removed from tissues. Blood cells are not excreted from the body
unless they are first broken down into nitrogenous wastes in the liver.
(3) The rate of digestion increases is not the statement that best describes a change that
usually takes place in the human body when the heart rate increases as a result of
exercise. During vigorous exercise, the body normally suspends all nonessential life
activities in order to ensure that sufficient resources are delivered to muscle cells. In this
case, the rate of digestion would decrease, not increase, during exercise.
(4) No hormones are produced is not the statement that best describes a change that
usually takes place in the human body when the heart rate increases as a result of
exercise. Hormones are produced as needed to meet the body's demands for the control
of metabolic activities in its tissues.
1 13. In the cells of the human body, oxygen and glucose molecules are used directly in a
process that
1. releases energy 3. builds red blood cells
2. digests foods 4. alters the DNA of the cell
1 In the cells of the human body, oxygen molecules are used directly in a process
that releases energy. The life process described is known as aerobic respiration. In this
process, molecules of glucose are broken down into molecules of carbon dioxide and
water, with the resulting production of ATP molecules. ATP stores the chemical bond
energy released in aerobic respiration.
WRONG CHOICES EXPLAINED (2) It is not true that in the cells of the human body, oxygen molecules are used directly
in a process that digests fats. Fats are digested by a cellular chemical process, known as
hydrolysis, that breaks up larger organic molecules into smaller subunit molecules. The
process of fat digestion begins in the small intestine, where bile from the gallbladder
enters and emulsifies complex fat into globules for easier digestion in the small intestine.
(3) It is not true that in the cells of the human body, oxygen molecules are used directly
in a process that synthesizes carbohydrate molecules. The synthesis of carbohydrate
molecules (i.e., glycogen) occurs in the liver and does not require the presence of
oxygen.
(4) It is not true that in the cells of the human body, oxygen molecules are used directly
in a process that alters the genetic traits of the cell. Alterations of the genetic traits of a
cell are known as mutations. Mutations do not require the presence of oxygen in order to
occur.
2 14. What is an advantage of a change in pulse rate after exercising?
1. The heart needs to produce more energy
to supply the active muscle cells and
maintain homeostasis.
3. The blood is removing oxygen from
muscle cells that were not active and
carrying it to muscle cells that are active.
2. An increased blood flow carries excess
waste products (like lactic acid) away from
the active muscle cells.
4. The blood is supplying the active muscle
cells with carbon dioxide to neutralize
wastes in those cells.
2 An increased blood flow carries excess waste products away from the active muscle
cells is an advantage of a change in pulse rate after exercising. As the blood passes
through capillaries in muscle tissues, it absorbs carbon dioxide and other wastes from
these cells for excretion via the lungs, kidneys, and skin to the outside environment.
Increasing blood flow through muscle tissues accelerates the removal of these wastes.
WRONG CHOICES EXPLAINED (1) The heart needs to produce more energy to supply the active muscle cells and
maintain homeostasis is not an advantage of a change in pulse rate after exercising. The
heart does not produce energy. Rather, the heart circulates dissolved glucose and
hemoglobin-bound oxygen to active muscle cells. The mitochondria in muscle cells can
then convert the chemical bond energy of glucose into ATP energy, thereby maintaining
homeostasis.
(3) The blood is removing oxygen from muscle cells that were not active and carrying it
to muscle cells that are active is not an advantage of a change in pulse rate after
exercising. Once oxygen is released to muscle cells from the blood, the oxygen is not
then removed from those cells for transport elsewhere. Instead, the oxygen is used in the
cells to which it was first delivered.
(4) The blood is supplying the active muscle cells with carbon dioxide to neutralize
wastes in those cells is not an advantage of a change in pulse rate after exercising.
Carbon dioxide is a by-product (waste) of the respiratory reactions. Carbon dioxide is
removed from, not supplied to, muscle cells by the blood.
3 15. A student lifted weights after school and found that his muscles started to burn. He
couldn't continue to lift the weights after prolonged exercising. This muscle fatigue is
most likely due to
1. the heart beating too fast and tiring out 3. lack of oxygen in the muscles and build
up of lactic acid waste
2. the lungs accumulating oxygen 4. lack of carbon dioxide in the muscles
3 This muscle fatigue is most likely due to lack of oxygen and build up of waste in the
muscles. During periods of strenuous exercise, muscle cells quickly use up available
dissolved oxygen required for aerobic respiration. As a result, the cells resort instead to a
less-efficient form of anaerobic respiration known as lactic acid fermentation or
glycolysis. This process results in the production of a small amount of ATP energy and
the metabolic waste lactic acid. Lactic acid stimulates a pain response in the muscles
where it forms. This combination of factors is what we describe as muscle fatigue.
WRONG CHOICES EXPLAINED (1) This muscle fatigue is not most likely due to the heart beating too fast and tiring out.
Although an increased heart rate is typical during exercise, it is not the cause of muscle
fatigue.
(2) This muscle fatigue is not most likely due to the lungs accumulating oxygen. The
lungs function to absorb oxygen from the air and transfer the oxygen to the blood. This
activity is not the cause of muscle fatigue.
(4) This muscle fatigue is not most likely due to lack of carbon dioxide in the muscles.
Carbon dioxide is a waste product of aerobic respiration but not of lactic acid
fermentation. Carbon dioxide is not the cause of muscle fatigue.
1 16. A marathon runner frequently experiences muscle cramps and burning while running.
If he stops running and rests, the cramps eventually go away. The cramping and burning
in the muscles most likely results from
1. lack of adequate oxygen supply to the
muscle 3. the runner stretching before running
2. the runner running too slowly 4. breathing too much
1 The cramping of the muscles most likely results from lack of adequate oxygen supply
to the muscle. During periods of oxygen deprivation, muscle cells revert to an anaerobic
respiratory process known as lactic acid fermentation. During this process, lactic acid
builds up in the muscle cells, causing them to cramp. The lactic acid is also detected by
nerves in the muscle, sending a sensation of pain to the brain and thus alerting it to the
need to reestablish a proper oxygen level in the muscles.
WRONG CHOICES EXPLAINED (2) The cramping of the muscles does not most likely result from the runner running too
slowly. Usually running too fast for the body's capabilities, not too slowly, results in
muscle cramping.
(3) The cramping of the muscles does not most likely result from the runner warming up
before running. Warm-up techniques, in which the muscles are stretched and blood flow
increased, generally reduce the incidence of muscle cramping.
(4) The cramping of the muscles does not most likely result from increased glucose
production in the muscle. Glucose is produced in the muscles from the breakdown of
glycogen stored in the muscle cells and in the liver. Its increased production would have
little or no effect on the incidence of muscle cramping.
3 17. Base your answer on the information below and accompanying graph and on your
knowledge of biology.
Students were asked to design a lab that investigated the relationship between exercise
and heart rate. Heart rate was determined by recording the pulse rate in beats per minute.
The students hypothesized that increased exercise results in an increased heart rate. The
class results for the experiment are shown in the graph shown.
Which statement is best supported by the graph?
1. Before exercising, the average pulse rate
was 65; four minutes after exercising, the
average pulse rate was 65.
3. While exercising, the highest average
pulse rate was 150; before exercising, the
average pulse rate was 65.
2. After four minutes of exercising, the
average pulse rate was 120; two minutes
after exercising, the average pulse rate was
120.
4. Two minutes before exercising, the
average pulse rate was 80; after two minutes
of exercise, the average pulse rate was 140.
3 While exercising, the highest average pulse rate was 150; before exercising, the
average pulse rate was 65 is the statement best supported by the graph. An examination
of the graph shows that for the five minutes prior to the start of the exercise period, the
average pulse rate was uniformly at 65 beats per minute. During the first three minutes of
the exercise period, the average pulse rate rose quickly to 120. Then it more gradually
rose to 150 over the next seven minutes. Finally, the graph shows that the average pulse
rate began to decline as soon as the exercise period ended and reached 80 beats per
minute by five minutes past this period.
WRONG CHOICES EXPLAINED (1) Before exercising, the average pulse rate was 65; four minutes after exercising, the
average pulse rate was 65 is not the statement best supported by the graph. The graph
indicates that four minutes after exercising, the average pulse rate was approximately 85
beats per minute, not 65.
(2) After four minutes of exercising, the average pulse rate was 120; two minutes after
exercising, the average pulse rate was 120 is not the statement best supported by the
graph. The graph indicates that after four minutes of exercising, the average pulse rate
was approximately 135 beats per minute, not 120.
(4) Two minutes before exercising, the average pulse rate was 80; after two minutes of
exercise, the average pulse rate was 140 is not the statement best supported by the graph.
The graph indicates that two minutes before exercising, the average pulse rate was
approximately 65 beats per minute, not 85. After two minutes of exercise, the average
pulse rate was approximately 90 beats per minute, not 140.
3 18. Which statement accurately compares cells in the human circulatory system to cells
in the human nervous system?
1. Cells in the circulatory system carry out
the same exact function as cells in the
nervous system.
3. Cells in the nervous system are different
in structure from cells in the circulatory
system, and they carry out different
specialized functions.
2. Cells in the circulatory system are
identical in structure to cells in the nervous
system.
4. Cells in the nervous system carry out the
same exact function as cells in the
circulatory system.
3 Cells in the nervous system are different in structure from cells in the circulatory
system, and they carry out different specialized functions is the statement that accurately
compares cells that make up the circulatory and nervous systems of humans. Neurons, a
specific cell type found in the human nervous system, have a branched structure and are
specialized to conduct nerve impulses. By contrast, red blood cells and white blood cells
typically found in the human circulatory system are small cells whose principal functions
are to carry respiratory oxygen to body tissues and to destroy foreign antigens,
respectively.
WRONG CHOICES EXPLAINED (1) Cells in the circulatory system carry out the same life function for the organism as
cells in the nervous system is not a statement that accurately compares cells that make up
the circulatory and nervous systems of humans. The primary function of the red blood
cells of the human circulatory system is the transport of materials such as oxygen and
dissolved food around the body; that of white blood cells is the immune response. By
contrast, the primary function of the neuron is the regulation of bodily functions by
means of nerve impulse transmission.
(2) Cells in the circulatory system are identical in structure to cells in the nervous
system is not a statement that accurately compares cells that make up the circulatory and
nervous systems of humans. Cells of the human circulatory system are of several
different types (including red blood cells, white blood cells, lymphocytes, and platelets);
these cells tend to be small, discrete units. Human neurons also are of several types
(including sensory neurons, motor neurons, and interneurons) but differ from blood
tissues in that they are generally long and/or highly branched cells that cluster together in
nerves.
(4) Cells in the nervous system act independently, but cells in the circulatory system
function together is not a statement that accurately compares cells that make up the
circulatory and nervous systems of humans. Scientific research increasingly indicates
that the cells of all body systems act together in a coordinated fashion even though they
may not be physically connected.
3 19. Base your answer on the information below, on the accompanying data table, and on
your knowledge of biology.
A group of students obtained the following data while trying to determine the effect of
exercise on pulse rate.
Which two body systems were most actively involved in this experiment?
1. respiratory and immune 3. respiratory and circulatory
2. digestive and endocrine 4. immune and circulatory
3 Respiratory and circulatory are the two body systems that were most actively involved
in this experiment. Data provided in the table give information about pulse rate, which
directly involves the circulatory system. The student's general knowledge of biology is
needed to understand that the respiratory system functions to provide oxygen needed for
cellular respiration as well as to remove carbon dioxide and other metabolic wastes from
muscles involved in the exercise regimen.
WRONG CHOICES EXPLAINED (1), (4) Respiratory and immune and immune and circulatory are not the two body
systems that were most actively involved in this experiment. The immune system
provides the body with protection from foreign invaders and potentially dangerous
antigens. This system was not directly involved with this experiment.
(2) Digestive and endocrine are not the two body systems that were most actively
involved in this experiment. The digestive system functions to break down complex
foods into soluble molecules. The endocrine system manufactures hormones that
function to direct the activities of specific target tissues. These systems were not directly
involved with this experiment.
1 20. Base your answer on the accompanying information and on your knowledge of
biology.
An experiment was designed to test whether students could squeeze a clothespin more
times in one minute after resting or after exercise.
The experimental results could be made more valid by
1. increasing the number of students 3. using safety precautions
2. using a plastic clothespin 4. making a bar graph of the data
1 The experimental results could be made more valid by increasing the number of
students. Because the student subjects tested in this experiment are individuals whose
strength may vary greatly, a large number should be tested to ensure that the
experimental results are not based on too small a number of subjects. Instead, the results
should be based on an average representing the strengths and abilities of a large, typical
group of students. Using a large number of experimental subjects makes the experimental
results more valid by helping the researcher to avoid statistical error introduced when a
too-small subject group is used.
WRONG CHOICES EXPLAINED: (2) The experimental results could not be made more valid by using a plastic clothespin.
This factor should represent a constant condition of the experiment established by the
researcher as a part of the experimental method. Using a plastic clothespin does not make
the experimental results more valid.
(3) The experimental results could not be made more valid by using safety precautions.
Safety precautions should always be considered when conducting scientific research.
This factor should represent a constant condition of the experiment established by the
researcher as a part of the experimental method. However, using safety precautions does
not make the experimental results more valid.
(4) The experimental results could not be made more valid by making a bar graph of the
data. Graphical representations of raw data help the researcher to analyze the results of
the experiment, but they do not make the experimental results more valid.
3 21. An experiment was carried out to determine whether drinking caffeinated soda
increases pulse rate. The pulse rates of two groups of people at rest were measured.
Group A was then given caffeinated soda and group B was given caffeine-free soda. One
hour after drinking the soda, the pulse rates were measured. The participants in the
experiment were all the same age, and they were all given the same amount of soda.
The dependent variable in this experiment is the
1. type of soda given to each group 3. pulse rate of each group
2. amount of soda given to each group 4. age of participants in each group
3 The dependent variable in this experiment is the pulse rate of each group. A dependent
variable is what is measured in an experiment and what is affected by other conditions
present in the experiment. The dependent variable responds to the independent variable.
It is called dependent because it depends on the independent variable. This researcher is
testing the effect of caffeinated/caffeine-free soda (independent variable) on pulse rate
(dependent variable).
[Note: This experimental design is flawed in that it does not contain a true control group,
which might be a third group who drink only water.]
WRONG CHOICES EXPLAINED (1) The dependent variable in this experiment is not the type of soda given each group.
The type of soda given each group is the independent variable of this experiment. An
independent variable is the condition in the experiment manipulated by the researcher.
(2), (4) The dependent variable in this experiment is not the amount of soda given to each
group or the age of participants in each group. These conditions of the experiment are
constants that are consciously controlled by the researcher so they do not vary from
group to group. The use of constants in an experiment helps to ensure that the
independent variable (type of soda), and not some other condition, affects the dependent
variable (pulse rate).
3 22. A student conducted an experiment to determine if listening to different types of
music would affect pulse rate. She thought that pulse rate would change with different
types of music. Each person participating in her experiment listened to seven different
selections of music for 30 seconds each. The pulse rates were taken after each 30-second
interval of music. Based on her experiment, the student concluded that a person's pulse
rate changed when listening to different types of music.
The component missing from this experiment is a
1. prediction 3. control group
2. hypothesis 4. research plan
3 The component missing from this experiment is a control group. A control group is a
second group that is subjected to all of the conditions of the experiment with the
exception of the independent variable being studied (music). The control group helps the
researcher to determine the validity of the experiment by eliminating the possibility that
the dependent variable (pulse rate) is being affected by unrecognized stimuli. This
student's control group might have been a second group of people who sat next to
members of the experimental group and who experienced all the same stimuli except the
music selections heard by the experimental group.
WRONG CHOICES EXPLAINED (1), (2) The component missing from this experiment is not a prediction or a hypothesis.
A hypothesis is a scientific term referring to a researcher's educated guess about the
results of an experiment. In this case, the hypothesis is about the effect of an independent
variable (music) on a dependent variable (pulse rate). The term prediction has essentially
the same meaning in general language. The student's hypothesis/prediction is captured in
the sentence "she thought that pulse rate would change with different types of music."
(4) The component missing from this experiment is not a research plan. A research plan
is a set of tasks needed to test the effect of an independent variable (music) on a
dependent variable (pulse rate). The student's research plan is captured in the following
sentences, "Each person participating in her experiment listened to seven different
selections of music for 30 seconds each. The pulse rates were taken after each 30-second
interval of music."
2 23. A student squeezes a clothespin as rapidly as possible for one minute. Without
stopping to rest, the student continues to squeeze the clothespin for a second minute. At
the end of the second minute, the student's fingers and hand feel very cramped and tired.
The physical tiredness and cramping in the muscles in the student's hand were most
likely due to the increased production of
1. energy (ATP) 3. oxygen
2. waste products (lactic acid) 4. glucose (sugar)
2 The physical tiredness and cramping in the muscles in the student's hand were most
likely due to the increased production of waste products. When muscles are exercised
strenuously, muscle tissues quickly use up available oxygen needed for the process of
aerobic respiration. At this point the cells begin to carry on a type of anaerobic
respiration known as lactic acid fermentation. Lactic acid is the waste product of this
process that builds up in muscle cells and causes the feelings of cramping and tiredness
in the muscle.
WRONG CHOICES EXPLAINED (1) The physical tiredness and cramping in the muscles in the student's hand
were not most likely due to the increased production of ATP. ATP (adenosine
triphosphate) is an energy-rich compound that is produced as a result of the respiratory
reactions. The presence of ATP in the muscles would decrease, not increase, feelings of
cramping and tiredness in the muscles.
(3) The physical tiredness and cramping in the muscles in the student's hand
were not most likely due to the increased production of oxygen. Oxygen is used, not
produced, in muscle cells.
(4) The physical tiredness and cramping in the muscles in the student's hand
were not most likely due to the increased production of glucose. Glucose is used, not
produced, in muscle cells.
3 24. Base your answer on information below and accompanying graph and on your
knowledge of biology.
Students were asked to design a lab that investigated the relationship between exercise
and heart rate. Heart rate was determined by recording the pulse rate in beats per minute.
The students hypothesized that increased exercise results in an increased heart rate. The
class results for the experiment are shown in the graph shown.
The change in heart rate that occurs between 1 and 5 minutes of exercise is an adaptation
that
1. reduces the rate at which oxygen is
carried to the muscle cells
3. results in the production of more energy
(ATP) in muscle cells
2. increases the rate at which carbon dioxide 4. slows the destruction of bacon involved
is carried to the muscle cells in breathing of muscle cells
3 The change in heart rate that occurs between 1 and 5 minutes of exercise is an
adaptation thatresults in the production of more ATP in muscle cells. Red blood cells in
the bloodstream absorb and carry oxygen for use by cells throughout the body. During
exercise, an elevated heart rate increases blood flow to the muscles. Oxygen is released
into muscle cells from the blood and transported in the cytoplasm to the mitochondria.
Respiratory enzymes in the mitochondria use this oxygen to release energy from the
chemical bonds of glucose and to store that energy temporarily in molecules of ATP.
Finally, ATP supplies the muscle cell with the energy needed for continued exercise.
WRONG CHOICES EXPLAINED (1) It is not true that the change in heart rate that occurs between 1 and 5 minutes of
exercise is an adaptation that reduces the rate at which oxygen is carried to the muscle
cells. The rate at which oxygen is carried to the muscle cells is increased by this change
in heart rate, not reduced.
(2) It is not true that the change in heart rate that occurs between 1 and 5 minutes of
exercise is an adaptation that increases the rate at which carbon dioxide is carried to the
muscle cells. Carbon dioxide, a waste product of respiration, is removed from muscle
cells, not carried to them, by the blood.
(4) It is not true that the change in heart rate that occurs between 1 and 5 minutes of
exercise is an adaptation that slows the destruction of enzymes involved in respiration of
muscle cells. Enzymes have a finite number of reactions they can catalyze before they are
recycled. Elevated heart rate neither speeds up nor slows down their destruction.
3 25. In an experiment to determine the effect of exercise on pulse rate, a student checks
his pulse rate before and after exercising for several minutes. The purpose of checking
his pulse rate before exercising is that it
1. serves as the conclusion for the
experiment 3. serves as a control for the experiment
2. is needed to justify the sample size 4. is needed to formulate a hypothesis
3 The purpose of checking his pulse rate before exercising is that it serves as a control
for the experiment. A control is an element of an experiment. A control is identical to the
experimental group in all respects except for the independent variable, which is the
variable controlled by the experimenter. If the student seeks to test the effect of exercise
on his pulse rate (dependent variable), then measuring his resting pulse rate establishes a
baseline. Then the student can compare his resting pulse rate (control) with his pulse rate
after exercising for several minutes.
WRONG CHOICES EXPLAINED (1) The purpose of checking his pulse rate before exercising is not that it serves as the
conclusion for the experiment. A conclusion is a statement by the experimenter
concerning the knowledge gained after conducting a scientific experiment. Checking the
student's resting pulse rate does not constitute an experimental conclusion.
(2) The purpose of checking his pulse rate before exercising is not that it is needed to
justify the sample size. The sample size for this experiment is one subject, the
experimenter himself, and cannot be justified by this means. This is a nonsense distracter.
(4) The purpose of checking his pulse rate before exercising is not that it is needed to
formulate a hypothesis. A hypothesis is a statement of the probable outcome of a
scientific experiment. Hypotheses are typically developed from the experimenter's prior
research into an area of inquiry. Checking the student's resting pulse rate does not
constitute an experimental hypothesis.
4 26. The list below includes three organ systems that are DIRECTLY used when a human
runs.
circulatory system
muscular system
skeletal system
Which one of the following systems should also be included in the list?
1. immune system 3. digestive system
2. reproductive system 4. nervous system
4 The nervous system is the system that should also be included in the list. When a
person engages in a physical activity such as running, the nervous system is fully
involved in such neural activities as conscious decision making, motor coordination,
reflex, and autonomic control of the rates of breathing and heartbeat. This neural control
allows the body to maintain homeostasis even while under the stress of the physical
activity.
WRONG CHOICES EXPLAINED (1) The immune system is not the system that should also be included in the list.
Although the immune system is constantly at work protecting the body from infectious
disease, this action is not directly related to the physical activity of running.
(2) The reproductive system is not the system that should also be included in the list.
Although the reproductive system is constantly at work preparing the body for the
production of offspring, this action is not directly related to the physical activity of
running.
(3) The digestive system is not the system that should also be included in the list.
Although the digestive system is constantly at work processing foods that provide the
body with materials and energy, this action is not directly related to the physical activity
of running.
1 27. A student measures his pulse rate while he is watching television and records it. Next,
he walks to a friend's house nearby and when he arrives, measures and records his pulse
rate again. He and his friend then decide to run to the mall a few blocks away. On
arriving at the mall, the student measures and records his pulse rate once again. Finally,
after sitting and talking for a half hour, the student measures and records his pulse rate
for the last time.
Which graph best illustrates the expected changes in his pulse rate according to the
activities described above?
1 Graph 1 is the graph that best illustrates the expected changes in pulse rate as described
in the passage. While watching television, the student starts with a low resting pulse rate.
A vigorous walk increases his pulse rate to a moderate level. Running a distance
increases his pulse to a high rate as his body demands increased transport of oxygen to
the muscles. Finally, after a rest period, the pulse rate drops to a rate just above the
original resting pulse.
WRONG CHOICES EXPLAINED (2), (3), (4) Graphs 2, 3, and 4 are not the graphs that best illustrate the expected changes
in pulse rate as described in the passage. High pulse rates are normally associated with
periods of exercise, while low pulse rates are normally associated with periods of rest.
See explanation above.
4 28. Students in a science class took their pulse rates before and after they ran in place for
one minute. The class data showed that pulse rates increased with exercise. A graph of
the data would look most like (see accompanying graphs)
4 A graph of this data would look most like graph 4. If measurements of pulse rate are
taken at only two points (before exercise and after exercise), the first value will be lower
than the second value. The line connecting these two data points will be an ascending
straight line as shown in graph 4.
WRONG CHOICES EXPLAINED (1), (2), (3) A graph of this data would not look most like graphs 1, 2, or 3. The shapes of
these graphs do not match the predicted shape based on the data description provided in
the question.
3 29. As part of an experiment, the heart rate of a person at rest was measured every hour
for 7 hours. The data are shown in the accompanying table.
Which graphed line best represents this data? (HINT: Draw your own graph on the side)
3 Graph 3 has the graphed line that best represents these data. The graphed line, like the
data in the table, gradually decreases, then increases nearly to the starting point. To
properly graph this data set, the horizontal (x) axis should be labeled "Hour" and
numbered 1 through 7; the vertical (y) axis should be labeled "Heart Rate" and numbered
10 through 80 (increments of 10).
WRONG CHOICES EXPLAINED (1), (4) Graphs 1 and 4 do not have the graphed lines that best represent these data.
Neither of these graphs has points that have been placed on the grid correctly.
(2) Graph 2 does not have the graphed line that best represents these data. In this graph,
the labels and numbering of the axes have been reversed from the method described
above. By convention, time is always marked on the horizontal (x) axis of a line graph.