Big Idea 2: Energy & Molecules for Growth, Repro, Homeo.
5.
1.
The graph above represents G (Gibbs free energy) vs. time. Which best describes the G? [2.1]
A) G < 0
B) G > 0
C) G = 0
D) G ≥ 0
2.
Which of the following would have reaction thermodynamics that resemble the graph above? [2.1]
A) The use of RuBisCo to react carbon dioxide with ribulose 1,5-biphosphate to eventually yield
3-phosphoglycerate.
B) The glycolysis step of producing pyruvate from glucose.
C) The reaction of fatty acids and glycerol to yield triglycerides.
D) None of the above responses resemble the graph above.
3.
The monarch butterfly caterpillar has 17% efficiency with consumption to growth. For a specific
period of time, if the mass of a group of caterpillars increases from 128g to 278g, what mass of
plants did the caterpillars eat? [2.1]
A) 150g
B) 1500g
C) 880g
D) 570 g
Pictured above is a person jumping from a diving platform into water. Due to gravity, objects move
spontaneously from a higher altitude to a lower one. As the person jumps from the platform and
into the water, stability is met. This process is... (2.4)
A) Endergonic, because energy is absorbed in the process of becoming more stable
B) Exergonic, because energy is released in the process of becoming more stable
C) Exergonic, because O2 is required for the sustainment of life
D) Endergonic, because cells release free energy in a series of reaction
∆G = ∆H - T∆S
6.
In the equation above, ∆G represents free energy. Which is true about ∆G? (2.5)
A) It is negative in an exergonic reaction
B) It is positive in an exergonic reaction
C) It is negative in an endergonic reaction
D) It may be either positive OR negative in an endergonic reaction
7.
(GRID-IN) A group of cuboidal cells in a kidney are involved in the diffusion of waste from the
bloodstream into nephrons. Find the surface area to volume ratio of one of these cuboidal cells that
has a length of 20 micrometers. [2.6]
8.
What is released at the question mark in the diagram? [2.5]
?
4.
GRID-IN: The exergonic reaction above has a △G value of -56 kJ/mol and a △S value of 20
kJ/mol•K. The endergonic reaction has a △G value of 43 kJ/mol and △S of -20 kJ/mol•K. The
reactions occur at 295K. In the coupling of these two reactions, what is the value for change in
gibbs free energy, where △G = △H - T△S? [2.1]
A)
B)
C)
D)
water
sunlight
carbon dioxide
oxygen
12. Aerobic respiration does not take place without oxygen available, because oxygen… [2.9]
A) is the terminal electron acceptor in respiration.
B) is necessary for glycolysis.
C) is essential for the formation of carbon dioxide.
D) is present in alcohol and lactic acid.
13. The fluid mosaic model of S.J. Singer and G.L. Nicolson created in 1972 replaced the earlier model
proposed by Davson and Danielli. Which of the following shows an example of the fluid mosaic
model. [2.10]
9.
Cellular respiration is the set of the metabolic reactions and processes that take place in the cells of
organism to convert biochemical energy from nutrients into adenosine triphosphate (ATP). Which
step of cellular respiration will generate ATP regardless of whether oxygen is present or not? [2.5]
A) Krebs cycle
B) Oxidative phosphorylation
C) Glycolysis
D) Electron transport chain
10. Referring to the diagram above, in the absence of oxygen, the cell’s ability to convert the stored
energy of glucose to usable ATP… [2.5]
A) is greatly increased.
B) is greatly decreased, but not zero.
C) is zero.
D) is unchanged.
11. Which of the following explanations is correctly paired with the choices below? [2.6, 2.7]
A) Block A has the greatest ratio of surface area to volume, thus more volume in needed for a
more efficient rate of intake of nutrients and elimination waste.
B) Block D has the lowest ratio of surface area to volume so more cellular structures are necessary
to exchange materials with the environment.
C) Block A has the greatest ratio of surface area to volume ratio so the exchange rate of materials
to the external environment is efficient due to the small amount of plasma membrane
D) All blocks have the diffusion rate and all adequately exchange materials with the environment.
A)
B)
C)
D)
14. One of the following molecules in the diagram below has been incorrectly shown as to whether it
can pass through the phospholipid bilayer of a eukaryotic cell of the American black bear, which
lives on land in mild climates, and eats a diet consisting mostly of berries.Which molecule has been
shown incorrectly? [2.11]
15. Outside of a cell a large abundance of a certain molecule that the cell needs is present compared to
inside the cell. This molecule is larger than water molecules and is attracted to water molecules. This
molecule is needed in the development of cells and is involved in the movement of organelles.
Which image best explains how the molecule can pass through the phospholipid bilayer? (2.10, 2.9,
2.11, 2.12)
17. Which of the following will most easily diffuse through a cell membrane? [2.10]
A)
B)
C)
D)
Stomata in Plants and Temperature
In humans, food enters through the mouth, and travels through the pharynx and esophagus to the stomach,
where smooth muscle provides mechanical digestion and HCl acid denatures proteins. Enzymes in the
small intestine (and stomach) provide chemical digestion. In the intestines, water and various monomers
are absorbed. The remainder of the meal is released as feces. The diagram below compares the amount (in
kilograms) of feces discarded annually at different stages of the life cycle for various species. [2.9]
Temperature (C)
0
10
20
30
Percent Stomata Open
88
54
33
7
Transpiration rate (mmol/m2sec)
.2
1.3
4.6
3.8
18. A plant is subjected to environments with different temperatures to see how a plant reacts in
different temperatures. The percent of the plant’s stomata that are open are calculated at each
temperature, and the transpiration rate is calculated. Transpiration is the loss of water vapor through
a stomata in a plant. What is the best conclusion that can be made from this data? [2.12]
A) As temperatures increase, plants close their stomata to prevent water loss
B) Lower epidermis stomata are used to prevent rapid water loss
C) Plants use stomata for gas exchange as well
D) As temperature increases, gas exchange decreases because of the closed stomata
19. Which does NOT support the idea that eukaryotic mitochondria descend from bacteria? [2.13]
A) mitochondria divides independently from nucleus
B) mitochondria have two membranes
C) mitochondrial ribosomes
D) all of these support the idea that mitochondria came from a bacterium
16. How does this graph represent the exchange of molecules between an organism and it’s environment
and its subsequent use of these molecules to build new molecules for growth, homeostasis and
reproduction? (2.9)
A) Orangutans, macaques, gorillas, and chimpanzees are all primarily fruit eaters, so this graph
shows that they interact with their environment by eating the fruit and by excreting their feces.
B) All of the above organisms consume the most amount of food during their reproductive ages,
which suggests that these organisms use the molecules they consumed for reproduction. In
their infant through juvenile stages, the organisms have clearly grown, suggesting once more
that the substances they ate went towards growth and homeostasis.
C) The human column is different from the rest, especially in that there is a weaning period in
between the two infant stages. This suggests that human babies gain their nutrients from
weaning and that this facilitates growth.
D) All of the above are correct.
20. Vancomycin (left) is a powerful glycopeptide
antibiotic used in the treatment of gram-positive
bacterial infections. What is the best explanation as
to why vancomycin is relatively nontoxic to human
cells? [2.14]
A) It destroys the glycopeptide layers within
eukaryotic cell membranes.
B) Humans have evolved resistance to
vancomycin whereas bacteria have not.
C) Peptidoglycan is not present in high enough
amounts in human cells for vancomycin to
present a problem.
D) Bacteria are so evolutionarily distant from
humans that most bacterial structures,
proteins, etc. are suitable targets for
antibiotics.
24. LDL is found in virtually all mammals. However, in one case ,a person has a mutation in their DNA
on the intron for LDL receptors. This changes the shape of the LDL receptor. What problems will
this person’s cells have? (2.15)
A) The cell will become healthier because cholesterol blocks diffusion across the membrane,
preventing molecules from entering or leaving the cell passively.
B) The cell’s nucleus if will stop sending mRNA since cholesterol will not act as a hormone and
signal for transcription factors
C) The firmness and integrity of plasma membrane will either become overly fluid or solid
D) Neuron signalling will increases in efficiency since cholesterol will not hinder the development
of the myelin sheath
21. Prokaryotes were the only form of life on Earth for millions of years until eukaryotic cells evolved.
Differences in cellular structure of prokaryotes and eukaryotes include the presence of mitochondria.
It was once thought that prokaryotic cells did not possess cytoskeletons, but advances in imaging
technology and structure determination led to the discovery of filaments in these cells in the early
1990s. Which of the following statements is a correct distinction between prokaryotic and
eukaryotic cells attributable to the absence of a prokaryotic cytoskeleton? [2.14]
A) Organelles are found only in eukaryotic cells
B) Cytoplasmic streaming is not observed in prokaryotes
C) Only eukaryotic cells are capable of movement
D) Only the eukaryotic cell concentrates its genetic material in a region separate from the rest of
the cell
22. One of the most significant differences between prokaryote and eukaryote structures is... [2.14]
A) Prokaryotes have cell walls while Eukaryotes do not
B) Eukaryotes have organelles, while Prokaryotes do not
C) Eukaryotes can’t do photosynthesis, whereas prokaryotes can
D) Prokaryotes have no inner membrane around their DNA
LDL, low density-lipoprotein, is a lipoprotein, enriched in cholesterol, that has a LDL receptor which,
when the ligand bind to it, starts receptor mediated endosymbiosis. This method allows the cell to intake a
large amount of LDL compared to diffusion. When LDL enters the cell it is delivered to an endosome and
then to a lysosome where cholesterol is “freed” from LDL. Cholesterol is then released for use in the cell
like in the plasma membrane. Below is a chart of the number of LDL receptors, LDL present, and
cholesterol.
Time
(hours)
2
4
6
8
10
12
LDL Receptors
LDL (in cell)
Cholesterol
122
157
138
53
42
123
50
152
147
61
51
47
21
57
167
150
45
23
23. Which statement accurately depicts the relationship between LDL and cholesterol? (2.8-11, 16,-19)
A) LDL and cholesterol are both found in the plasma membrane, so they often come into contact
with each other.
B) High levels of cholesterol lower the amount of LDL receptors by inhibiting the production of
LDL receptors on the plasma membrane.
C) High levels of LDL stimulates the cell to produce more mRNA coding for LDL receptors
D) When the cell undergoes cell growth, the production of LDL molecules increases, enabling the
cell to have more cholesterol.
25. Which of the following examples of cells is most distantly related to the rest? (2.14)
A)
B)
C)
D)
26. In an animal cell, there are many compartments that perform different functions. What explanation
shows how internal membranes and organelles contribute to cell function? (2.13)
A) Internal membranes facilitate cellular processes by increasing surface area where reactions can
occur.
B) Membranes and membrane-bound organelles in eukaryotic cells ensure that all enzymatic
reactions take place in the same pH and osmotic conditions.
C) Mitochondria, lysosomes, and chloroplasts are examples of endosymbiosis that have become
part of the cell’s internal membrane systems.
D) None of the above
27. Glutamine is one of the 20 amino acids required to build proteins. It is not recognized as an essential
amino acid but is required in certain situation. In the chemical reaction that combines glutamic acid
and ammonia, glutamine is formed, however this process is endergonic and the change in G is +3.4.
In order for this reaction to occur it needs to be coupled with a reaction that has a negative change in
G. The reaction that breaks down ATP to ADP and a phosphate has a change in G of -7.3. What
would be the overall change in G? [2.16]
In order to begin the monthly hormonal cycle for
women, the hypothalamus must first secrete a releasing
hormone to the pituitary gland, called GnRH. This
hormone initiates a negative feedback loop that
regulates women’s reproductive cycles. The pituitary
gland releases Follicle Stimulating Hormone (FSH)
which is received in the ovaries and signals them to
begin preparing an ovum. The ovaries respond by
sending the sex hormone estrogen which effectively
signals the hypothalamus to stop signaling the pituitary
gland to produce FSH. Estrogen also informs the
uterine lining to begin preparation for the egg. [2.15]
28. What would happen if an estrogen inhibitor was
injected into the bloodstream after the pituitary
gland had already started producing FSH? [2.15]
A) Nothing, the female reproductive cycle
doesn’t need estrogen.
B) If estrogen is inhibited, the pituitary gland
would stop making FSH and no egg would
be prepared for fertilization.
C) If estrogen is inhibited, the pituitary gland
will continue making FSH and follicle
stimulation will continue.
D) If estrogen is inhibited, then the pituitary
gland will continue making FSH and the
uterine lining will not prepare for the egg.
29. According to the diagram of a positive feedback loop above; which of the following would not
constitute a positive feedback loop? [2.19]
A) Ethylene gas causing fruit ripening
B) Hormones leading to birth contractions
C) running cattle causing a cattle stampede
D) hormone pathway for insulin regulation
30. Everything from cells to organisms to ecosystems is in a state of dynamic balance that must be
controlled by positive or negative feedback mechanisms. Positive feedback mechanisms amplify
responses and processes in biological organisms. Which of the following is not an example of
positive feedback? (Refer to diagram of #14) [2.19]
A) Operons in gene regulation
B) Lactation in mammals
C) The process of blood clotting
D) Ripening of fruit
31. The image above shows a banana, Musa acuminata, after several days of being exposed to ethylene,
a hormone produced by plants. In addition to inducing apoptosis, ethylene also results in the fruit
softening and changing color. Production is increased as the banana ripens and the hormone causes it
to ripen faster. The banana on day one is exposed to minimal amounts of ethylene, but as it becomes
riper the process is sped up and after one week the banana is nearly completely brown and is
producing much more ethylene than the banana on day one. Ethylene production in bananas is most
similar to which process? [2.20]
A) progesterone production in the week after ovulation
B) release of oxytocin during labor contractions
C) release of glucagon when as a response to low blood sugar
D) production of abscisic acid in bananas
32. In order to maintain homeostasis the body employs negative feedback loops. However, other
processes involve positive feedback. Which would be regulated by positive feedback? [2.20]
A) increased blood pressure
B) insulin secretion
C) slowed heart rate
D) uterine contractions
33. Cellular respiration is the process by which organisms convert food and nutrients into the accessible
energy currency ATP (adenosine triphosphate). This process can utilize glucose and oxygen. Above
is a diagram of the various stages of the process; first, a glucose is broken down into 2 pyruvate
sugars, which then enter the citric acid cycle. An organism is placed in a sealed container and levels
of alcohol are measured. At the end of the experiment, the alcohol concentration has doubled. Which
of the following is not a reasonable conclusion? [2.21]
A) The organism must consume more to make up for lost ATP.
B) Tf the organism is a plant, sunlight is not entering the container.
C) Oxygen cannot enter the container.
D) The organism’s metabolism has slowed down.
34. Almost all life on earth is directly or indirectly reliant on primary production. The organisms
responsible for primary production are known as primary producers or autotrophs. In terrestrial
ecoregions, these are mainly plants, while in aquatic ecoregions algae are primarily responsible.
Primary production is distinguished as either net or gross, which of the following is the most
efficient way of calculating the net primary production? [2.23]
A) Subtract the amount of cellular respiration from the gross primary production.
B) Use remotely sensed images of 2.67 sq. meters of plant traits or harvesting plant material on
the ground to estimate the net primary production.
C) Divide gross primary production by cellular respiration and square the product.
D) Recreate desired ecoregion in a 1 sq. meter glass container, allow time for photosynthesis to
occur, quantify the newly produced biomass in the glass bottle and multiply that amount by the
number of square feet in desired ecoregion.
35. GRID-IN: In a chaparral ecosystem, hawks are the tertiary consumers, preying on almost all of the
other consumers, as shown in the diagram. The grass produces 460 J of energy per square meter of
biomass on average, and there are approximately 2 rabbits and one snake for every ten square meters
of grass. The populations fluctuate mildly but consistently as the predator and prey populations are
close to equilibrium. How many times more energy will the hawk get from the grass if it eats the
rabbit instead of the snake? [2.23]
36. Paramecium are unicellular organisms that are widespread in marine environments. They are easily
cultivated and divide quickly, which makes them ideal for use in scientific experiments. The graph
above represents the amount of two types of paramecium over time, in a specific niche. What
ecological relationship may be occurring between the two species of paramecium represented by
these lines? [2.24]
A)
B)
C)
D)
Competition
Mutualism
Commensalism
Predator-Prey
37. In order to function, respiratory systems must be wet, have a high surface area, and a thin membrane;
oxygen is required as well. Underwater is by nature a wet environment, but water also has less
oxygen. There is plenty of oxygen in the air for land organisms, but the environment is dry.
Therefore, two systems are needed to adjust to these different environments. Respiratory systems in
organisms are generally divided into two categories: gills for organisms that live underwater, and
lungs for organisms that live on land. Dipnoi, known as lungfish, are known to have both gills and
lungs, as shown in the diagram above. The existence of both gills and lungs in lungfish demonstrate
which of the following? [2.25]
A) The countercurrent exchange system in gills works with the lungs to produce a more efficient
respiratory system in lungfish.
B) It demonstrates a mutation that led to faulty gills; lungs were needed in order for the lungfish to
survive as a species.
C) The environmental changes lead to the evolution of organisms with lungs instead of gills;
lungfish are an intermediary in this process.
D) Lungs are more efficient than gills.
38. Tobacco is made from the dried leaves of plants of Nicotiana. One of the diseases that affects
tobacco plants is angular leaf spot, caused by Pseudomonas amygdali pv. tabaci. Tobacco plants in
certain parts of Missouri have been greatly impacted by this disease. There have been five outbreaks
in the last century; the table above shows the number of plants before and after each outbreak for a
specific tobacco farm. Which of the following conclusions can be drawn from the above data? [2.28]
A) Fewer tobacco plants died by the fifth outbreak than in the first because the plants developed a
resistance to the disease.
B) Less tobacco plants died by the fifth outbreak than in the first because farmers were able to
give the plants better treatments as improvements have been made in science.
C) Every time an outbreak occurred, the dynamic homeostasis of the tobacco plants were
disrupted, leading to the death of many tobacco plants.
D) More tobacco plants died by the fifth outbreak than in the first because Pseudomonas
amygdali pv. tabaci has become stronger over the years and more lethal.
39. The purpose of the excretory system is to maintain osmolarity and to filter blood in order to get rid
of waste. Flatworms have holes on their backsides attached to protonephridia, which generate a
current that moves waste out of the holes and into the environment. Vertebrates use kidneys as part
of their excretory system, which flatworms lack. Inside the kidney is a unit called the nephron,
which includes a tube that that moves to the bladder, which eventually moves outside of the body.
The circulatory system that wraps around the tubule generates a current so that waste can move out
of the vertebrate. What accounts for the similarities in these excretory systems? [2.27]
A) The excretory system in flatworms and vertebrates show continuity due to common ancestry.
B) Vertebrates are closely related to flatworms and thus share many similarities.
C) It is pure coincidence that the two excretory systems are similar; flatworms and vertebrates are
not closely related and do not share a common ancestor.
D) No conclusions can be drawn because there is insufficient evidence of any relationship.
C)
40. Circadian rhythms are innate 24 hour cycles of behavior or physiological change that are
synchronized to external signals. In plants regulation of phytochrome is a circadian rhythm.
Phytochrome is a protein that has two isomers: Pfr absorbs far-red light and is converted to Pr and Pr
absorbs red light and is converted into Pfr. The ratio of these affects germination. In which one of
the following treatments would germination not occur? [2.28]
A) Blue light followed by a red light
B) Red light only
C) Red light and far red light simultaneously followed by red light only
D) Red light followed by far red light
41. When bacterial infections get past the bodies secondary immune response the body begins to employ
specific immune responses. Which of the following is a part of this response? [2.29]
A) Macrophages phagocytose a pathogen
B) Natural killer cells detect a difference in the MHC presented on an infected cells surface
C) Antibodies produced by B cells bind to a pathogen
D) Histamine is produced by a mast cell and triggers an inflammatory response
42. Chickenpox is caused by an infection of the varicella zoster virus, and is highly contagious. The
most obvious symptoms are the characteristic itchy rashes that can progress to small bumps and
blisters. Today, most babies are given a chickenpox vaccine to protect them from the virus in the
future. The vaccine is typically made from a weakened or killed form of the virus so that the body
will have the same immune response, but will not be in any danger. Which of the following
represents an immune response that would be specifically directed towards fighting the vaccine?
[2.30]
A)
B)
43. When studying normal organismal development, a team of researchers used a sensitive
immunological test that detects the presence of human chorionic gonadotropin (hCG) as early as 8 or
9 days after fertilization, monitored 112 pregnancies in normal women. Of these hCG-determined
pregnancies, 67 failed to be maintained. Of those 67, two-thirds failed before the placenta began to
produce progesterone. Which of the following is a possible explanation as to why these pregnancies
did not reach full term? [2.34]
A) Environmental factors mutated the mitotic machinery of the egg compromising its ability to
grow or implant in the uterine lining.
B) The eggs were not viable and therefore the fertilization was unsuccessful.
C) Mutations to the face, limbs, lungs and other organs which the fetus relies on the mother for
until birth, or mouth cause the embryo to be spontaneously aborted.
D) Most deformities develop in stage two of pregnancies and a miscarriage occurs.
44. Organ growth is not an autonomous process. It occurs within the context of a developing body and
must be coordinated across the whole organism so that each organ reaches its appropriate size at the
appropriate time. Regulatory mechanisms fall into four categories: (1) physiological mechanisms
that regulate the duration of organ growth; (2) plasticity mechanisms that regulate organ size in
response to changes in environmental factors; (3) patterning mechanisms that regulate organ size by
controlling the growth and differentiation of tissues within the organ; and (4) physical mechanisms
that regulate organ size in response to mechanical force. The above figure leads to the conclusion
that: [2.36, 2.33]
A)
B)
C)
D)
Timing and coordination of physiological events involve regulation
Timing and coordination of physiological events are necessary for normal development
Timing and coordination of of physiological events use many different mechanisms for
regulation
Both A and C are correct
45. In development, HOX genes often instruct cells that are not needed, such as soft tissue between
digits, to apoptose. This involves the synthesis of specific messenger RNA molecules and their
translation. PCD can sometimes be suppressed by inhibiting transcription or translation. What does
this tell you about cell apoptosis? [2.34]
A) That apoptosis is caused by cytoplasmic transcription factors initiated by signals from
neighboring cells that instruct the cell to apoptose
B) apoptosis of cells is only normal during embryonic development and is a sign of serious illness
otherwise.
C) this information could be useful in targeting cancer cells
D) the most important factor of cell apoptosis is the way a cell is instructed to apoptose. A few
different kinds influence the way it dies and exposes the rest of the body to its disease.
Year
Tobacco plants
before the outbreak
Tobacco plants
after the outbreak
1932
318
202
1947
469
335
1966
371
256
1981
352
240
1997
396
374
46. In plants, physiological events involve interactions between environmental stimuli and internal
molecular signals. In animals, internal and external signals regulate a variety of physiological
responses that synchronize with environmental cycles and cues. Which of the following is an
example of regulation in either plants or animals which are timed and coordinated? [2.37]
A) Phototropism
B) Photoperiodism
C) Circadian rhythms
D) Seasonal responses (e.g. hibernation)
E) All of these are examples of timed, regulated and coordinated physiological events
47. Which of the following does not support the claim that responses to information and communication
of information affect natural selection? [2.38]
A) A)The shaking of his tail feathers sounds like leaves rustling in the wind. The peacock faces
the peahen, with his rustling tail feathers and follows her around making loud mating calls
showing that he is strong and confident. If the peahen takes interest, she will allow the peacock
to mate with her.
B) The emperor penguin's mating ritual involves displays of both a visual and auditory nature, the
male stretches his head towards the sky while making 'trumpeting' sounds to attract a female
C)
D)
while he spreads his flippers to attract a mate. This shows his mate that he is strong and has
extra energy enabling him to exert energy to attract a mate and later care for young.
Birds and insects transfer pollen from the anther to the stigma of a plant, allowing plants to
reproduce
Female hedge sparrows only mate with male hedge sparrows who are small and dark with
shiny feathers, if a male hedge sparrow loses its sheen, females will not mate with him because
it’s a signal that he is weak
Day
Population at
beginning of
day
# of times
predators
sighted
# of warnings
given between
prairie dogs
Total # of responses
(fleeing before
predator attacks)
Population at
end of day
1
300
3
3
900
300
2
300
1
1
296
298
3
298
4
2
917
290
4
293
2
2
589
292
5
292
3
1
876
288
48. Cynomys ludovicianus, or Prairie Dogs, live in “towns” in North America’s prairies and grasslands.
They communicate with loud cries. A warning cry, for example, will send a town's denizens hustling
to their holes at the approach of a badger, coyote, or other predator. A second, "all-clear" call alerts
the community when the danger has passed. The figure above shows five days of data from a study
concerning prairie dog communication when in danger. What conclusions can be drawn from said
data? [2.38]
A) Prairie dogs are unobservant and care-free so predators are often able sneak up on them;
populations are only maintained because they breed quickly
B) Prairie dogs that do not understand the communications from their fellow prairie dogs are
disadvantaged and more likely to die because they don’t understand the warning; likewise they
put their population at risk if they do not warn others
C) Prairie dogs are intelligent and often don’t warn each other of coming predators so that they
can better escape
D) Prairie dogs have a highly structured social system in which any animal that fails to do its duty
of alerting the others of threats such as approaching predators is killed by the rest of the
community