Which of the following is responsible for the differences in summer and winter temperature stratification of deep temperate zone lakes?

Which of the following is responsible for the differences in summer and winter temperature stratification of deep temperate zone lakes? 

A) Water is densest at 4°C.
B) Oxygen is most abundant in deeper waters.
C) Winter ice sinks in the summer.
D) Stratification is caused by a thermocline.
E) Stratification always follows the fall and spring turnovers.






Answer: A

In temperate lakes, the surface water is replenished with nutrients during turnovers that occur in the

In temperate lakes, the surface water is replenished with nutrients during turnovers that occur in the 

A) autumn and spring.
B) autumn and winter.
C) spring and summer.
D) summer and winter.
E) summer and autumn.






Answer: A

Turnover of water in temperate lakes during the spring and fall is made possible by which of the following?

Turnover of water in temperate lakes during the spring and fall is made possible by which of the following? 

A) warm, less dense water layered at the top
B) cold, more dense water layered at the bottom
C) a distinct thermocline between less dense warm water and cold, dense water
D) the changes in the density of water as seasonal temperatures change
E) currents generated by nektonic animals





Answer: D

Generally speaking, deserts are located in places where air masses are usually

Generally speaking, deserts are located in places where air masses are usually 

A) tropical.
B) humid.
C) rising.
D) descending.
E) expanding.






Answer: D

What is the limiting factor for the growth of trees in the tundra?

What is the limiting factor for the growth of trees in the tundra? 

A) low precipitation
B) cold temperatures
C) insufficient minerals in bedrock
D) pH of soils
E) permafrost





Answer: E

Which series is correctly layered from top to bottom in a tropical rain forest?

Which series is correctly layered from top to bottom in a tropical rain forest? 

A) ground layer, shrub/immature layer, under story, canopy, emergent layer
B) canopy, emergent layer, under story, shrub/immature layer, ground layer
C) canopy, under story, shrub/immature layer, emergent layer, ground layer
D) emergent layer, canopy, under story, shrub/immature layer, ground layer
E) emergent layer, under story, canopy, ground layer, shrub/immature layer





Answer: D

Which of the following investigations would shed the most light on the distribution of organisms in temperate regions that are faced with climate change?

Which of the following investigations would shed the most light on the distribution of organisms in temperate regions that are faced with climate change? 

A) Remove, to the mineral soil, all of the organisms from an experimental plot and monitor the colonization of the area over time in terms of both species diversity and abundance.
B) Look back at the changes that occurred since the Ice Age and how species redistributed as glaciers melted, then make predictions on future distribution in species based on past trends.
C) Compare and contrast the flora and fauna of warm/cold/dry/wet climates to shed light on how they evolved to be suited to their present-day environment.
D) Quantify the impact of man's activities on present-day populations of threatened and endangered species to assess the rate of extirpation and extinction.
E) There is no scientific investigation that can help make predictions on the future distribution of organisms.





Answer: B

Coral reefs can be found on the southern east coast of the United States but not at similar latitudes on the southern west coast. Differences in which of the following most likely account for this?

Coral reefs can be found on the southern east coast of the United States but not at similar latitudes on the southern west coast. Differences in which of the following most likely account for this? 

A) sunlight intensity
B) precipitation
C) day length
D) ocean currents
E) salinity




Answer: D

Which of the following can be said about light in aquatic environments?

Which of the following can be said about light in aquatic environments? 

A) Water selectively reflects and absorbs certain wavelengths of light.
B) Photosynthetic organisms that live in deep water probably use red light.
C) Longer wavelengths penetrate to greater depths.
D) Light penetration seldom limits the distribution of photosynthetic species.
E) Most photosynthetic organisms avoid the surface where the light is too intense.





Answer: A

Which of the following are important biotic factors that can affect the structure and organization of biological communities?

Which of the following are important biotic factors that can affect the structure and organization of biological communities? 

A) precipitation, wind
B) nutrient availability, soil pH
C) predation, competition
D) temperature, water
E) light intensity, seasonality







Answer: C

If global warming continues at its present rate, which biomes will likely take the place of the coniferous forest (taiga)?

If global warming continues at its present rate, which biomes will likely take the place of the coniferous forest (taiga)? 

A) tundra and polar ice
B) temperate broadleaf forest and grassland
C) desert and chaparral
D) tropical forest and savanna
E) chaparral and temperate broadleaf forest







Answer: B

Air masses formed over the Pacific Ocean are moved by prevailing westerlies where they encounter extensive north-south mountain ranges, such as the Sierra Nevada and the Cascades. Which statement best describes the outcome of this encounter between a landform and an air mass?

Air masses formed over the Pacific Ocean are moved by prevailing westerlies where they encounter extensive north-south mountain ranges, such as the Sierra Nevada and the Cascades. Which statement best describes the outcome of this encounter between a landform and an air mass? 

A) The cool, moist Pacific air heats up as it rises, releasing its precipitation as it passes the tops of the mountains, and this warm, now dry air cools as it descends on the leeward side of the range.
B) The warm, moist Pacific air rises and cools, releasing precipitation as it moves up the windward side of the range, and this cool, now dry air mass heats up as it descends on the leeward side of the range.
C) The cool, dry Pacific air heats up and picks up moisture from evaporation of the snowcapped peaks of the mountain range, releasing this moisture as precipitation when the air cools while descending on the leeward side of the range.
D) These air masses are blocked by the mountain ranges, producing high annual amounts of precipitation on the windward sides of these mountain ranges.
E) These air masses remain essentially unchanged in moisture content and temperature as they pass over these mountain ranges.






Answer: B

Generalized global air circulation and precipitation patterns are caused by

Generalized global air circulation and precipitation patterns are caused by 

A) rising, warm, moist air masses that cool and release precipitation as they rise and then, at high altitude, cool and sink back to the surface as dry air masses after moving north or south of the tropics.
B) air masses that are dried and heated over continental areas that rise, cool aloft, and descend over oceanic areas followed by a return flow of moist air from ocean to land, delivering high amounts of precipitation to coastal areas.
C) polar, cool, moist high-pressure air masses from the poles that move along the surface, releasing precipitation along the way to the equator where they are heated and dried.
D) the revolution of Earth around the sun.
E) mountain ranges that deflect air masses containing variable amounts of moisture.







Answer: A

As climate changes because of global warming, species' ranges in the northern hemisphere may move northward, using effective reproductive adaptations to disperse their seeds. The trees that are most likely to avoid extinction in such an environment are those that

As climate changes because of global warming, species' ranges in the northern hemisphere may move northward, using effective reproductive adaptations to disperse their seeds. The trees that are most likely to avoid extinction in such an environment are those that 

A) have seeds that are easily dispersed by wind or animals.
B) have thin seed coats.
C) produce well-provisioned seeds.
D) have seeds that become viable only after a forest fire.
E) disperse many seeds in close proximity to the parent tree.






Answer: A

The success with which plants extend their range northward following glacial retreat is best determined by

The success with which plants extend their range northward following glacial retreat is best determined by 

A) whether there is simultaneous migration of herbivores.
B) their tolerance to shade.
C) their seed dispersal rate.
D) their size.
E) their growth rate.






Answer: C

Which of the following environmental features might influence microclimates?

Which of the following environmental features might influence microclimates? 

A) forest canopy
B) freshly plowed field
C) log on the forest floor
D) large boulder
E) All of the options are correct.






Answer: E

The main reason polar regions are cooler than the equator is that

The main reason polar regions are cooler than the equator is that 

A) there is more ice at the poles.
B) sunlight strikes the poles at a lower angle.
C) the poles are farther from the sun.
D) the polar atmosphere is thinner and contains fewer greenhouse gases.
E) the poles are permanently tilted away from the sun.






Answer: B

Imagine some cosmic catastrophe jolts Earth so that its axis is perpendicular to the orbital plane between Earth and the sun. The most obvious effect of this change would be

Imagine some cosmic catastrophe jolts Earth so that its axis is perpendicular to the orbital plane between Earth and the sun. The most obvious effect of this change would be 

A) the elimination of tides.
B) an increase in the length of night.
C) an increase in the length of a year.
D) a decrease in temperature at the equator.
E) the elimination of seasonal variation.






Answer: E

Which of the following events might you predict to occur if the tilt of Earth's axis relative to its plane of orbit was increased to 33 1/2 degrees?

Which of the following events might you predict to occur if the tilt of Earth's axis relative to its plane of orbit was increased to 33 1/2 degrees? 

A) Summers and winters in the United States would likely become warmer and colder, respectively.
B) Winters and summers in Australia would likely become less distinct seasons.
C) Seasonal variation at the equator might decrease.
D) Both northern and southern hemispheres would experience summer and winter at the same time.
E) Both poles would experience massive ice melts.






Answer: A

Deserts typically occur in a band at 20 degrees north and south latitude because

Deserts typically occur in a band at 20 degrees north and south latitude because 

A) descending air masses tend to be cool and dry.
B) trade winds have a little moisture.
C) moisture-laden air is heavier than dry air and is not carried to these latitudes.
D) ascending air tends to be moist.
E) these locations get the most intense solar radiation of any location on Earth.







Answer: A

In mountainous areas of western North America, north-facing slopes would be expected to

In mountainous areas of western North America, north-facing slopes would be expected to 

A) receive more sunlight than similar southern exposures.
B) be warmer and drier than comparable southern exposed slopes.
C) consistently be steeper than southern exposures.
D) support biological communities similar to those found at lower elevations on similar south-facing slopes.
E) support biological communities similar to those found at higher elevations on similar south-facing slopes.







Answer: E

Which of the following abiotic factors has the greatest influence on the metabolic rates of plants and animals?

Which of the following abiotic factors has the greatest influence on the metabolic rates of plants and animals? 

A) water
B) wind
C) temperature
D) rocks and soil
E) disturbances





Answer: C

Which statement describes how climate might change if Earth was 75% land and 25% water?

Which statement describes how climate might change if Earth was 75% land and 25% water? 

A) Terrestrial ecosystems would likely experience more precipitation.
B) Earth's daytime temperatures would be higher and nighttime temperatures lower.
C) Summers would be longer and winters shorter at midlatitude locations.
D) Earth would experience an unprecedented global warming.
E) More terrestrial microclimates would be created because of daily fluctuations in climate.






Answer: B

Palm trees and subtropical plants are commonplace in Land's End, England, whose latitude is the equivalent of Labrador in coastal Canada where the local flora is subarctic. Which statement best explains why this apparent anomaly exists between North America and Europe?

Palm trees and subtropical plants are commonplace in Land's End, England, whose latitude is the equivalent of Labrador in coastal Canada where the local flora is subarctic. Which statement best explains why this apparent anomaly exists between North America and Europe? 

A) Labrador does not get enough rainfall to support the subtropical flora found in Land's End.
B) Warm ocean currents interact with England, whereas cold ocean currents interact with Labrador.
C) Rainfall fluctuates greatly in England; rainfall is consistently high in Labrador.
D) Labrador is too windy to support tall plants, such as palm trees.
E) Labrador receives sunlight of lower duration and intensity than does Land's End.






Answer: B

What would be the effect on climate in the temperature latitudes if Earth were to slow its rate of rotation from a 24-hour period of rotation to a 48-hour period of rotation?

What would be the effect on climate in the temperature latitudes if Earth were to slow its rate of rotation from a 24-hour period of rotation to a 48-hour period of rotation? 

A) Seasons would be longer and more distinct (colder winters and warmer summers).
B) There would be a smaller range between daytime high and nighttime low temperatures.
C) Large scale weather events such as tornadoes and hurricanes would no longer be a part of regional climates.
D) Winter seasons in both the northern and southern hemispheres would have more abundant and frequent precipitation events.
E) The climate would stay the same. The only change would be longer days and nights.






Answer: E

Why is the climate drier on the leeward side of mountain ranges that are subjected to prevailing winds?

Why is the climate drier on the leeward side of mountain ranges that are subjected to prevailing winds? 

A) Deserts usually are found on the leeward side of mountain ranges.
B) The sun illuminates the leeward side of mountain ranges at a more direct angle, converting to heat energy, which evaporates most of the water present.
C) Pushed by the prevailing winds on the windward side, air is forced to rise, cool, condense, and drop its precipitation, leaving only dry air to descend the leeward side.
D) Air masses pushed by the prevailing winds are stopped by mountain ranges and the moisture is used up in the stagnant air masses on the leeward side.
E) More organisms live on the sheltered, leeward side of mountain ranges where their utilization of water lowers the amount available when compared to the windward side.







Answer: C

Which of the following choices includes all of the others in creating global terrestrial climates?

Which of the following choices includes all of the others in creating global terrestrial climates?

A) differential heating of Earth's surface
B) ocean currents
C) global wind patterns
D) evaporation of water from ocean surfaces
E) Earth's rotation on its axis







Answer: A

Which of the following might be an investigation of microclimate?

Which of the following might be an investigation of microclimate? 

A) the effect of ambient temperature on the onset of caribou migration
B) the seasonal population fluctuation of nurse sharks in coral reef communities
C) competitive interactions between various species of songbirds during spring migration
D) the effect of sunlight intensity on species composition in a decaying rat carcass
E) the effect of different nitrogen applications on corn productivity







Answer: D

Which of the following examples of an ecological effect leading to an evolutionary effect is most correct?

Which of the following examples of an ecological effect leading to an evolutionary effect is most correct? 

A) When seeds are not plentiful, trees produce more seeds.
B) A few organisms of a larger population survive a drought and then these survivors emigrate to less arid environments.
C) A few individuals with denser fur survive the coldest days of an ice age, and the reproducing survivors of the ice age all have long fur.
D) Fish that swim the fastest in running water catch the most prey and more easily escape predation.
E) The insects that spend the most time exposed to sunlight have the most mutations.







Answer: C

Which of the following levels of ecological organization is arranged in the correct sequence from most to least inclusive?

Which of the following levels of ecological organization is arranged in the correct sequence from most to least inclusive? 

A) community, ecosystem, individual, population
B) ecosystem, community, population, individual
C) population, ecosystem, individual, community
D) individual, population, community, ecosystem
E) individual, community, population, ecosystem






Answer: B

"How do seed-eating animals affect the distribution and abundance of the trees?" This question

"How do seed-eating animals affect the distribution and abundance of the trees?" This question

A) would require an elaborate experimental design to answer.
B) would be difficult to answer because a large experimental area would be required.
C) would be difficult to answer because a long-term experiment would be required.
D) is one that a present-day ecologist would be likely to ask.
E) All options are correct.








Answer: E

Which of the following is not required for a behavioral trait to evolve by natural selection?

Which of the following is not required for a behavioral trait to evolve by natural selection? 

A) In each individual, the form of the behavior is determined entirely by genes.
B) The behavior varies among individuals.
C) An individual's reproductive success depends in part on how the behavior is performed.
D) Some component of the behavior is genetically inherited.
E) An individual's genotype influences its behavioral phenotype.






Answer: A

Although many chimpanzees live in environments containing oil palm nuts, members of only a few populations use stones to crack open the nuts. The likely explanation is that

Although many chimpanzees live in environments containing oil palm nuts, members of only a few populations use stones to crack open the nuts. The likely explanation is that 

A) the behavioral difference is caused by genetic differences between populations.
B) members of different populations have different nutritional requirements.
C) the cultural tradition of using stones to crack nuts has arisen in only some populations.
D) members of different populations differ in learning ability.
E) members of different populations differ in manual dexterity.






Answer: C

A region of the canary forebrain shrinks during the nonbreeding season and enlarges when breeding season begins. This change is probably associated with the annual

A region of the canary forebrain shrinks during the nonbreeding season and enlarges when breeding season begins. This change is probably associated with the annual

A) addition of new syllables to a canary's song repertoire.
B) crystallization of subsong into adult songs.
C) sensitive period in which canary parents imprint on new offspring.
D) renewal of mating and nest-building behaviors.
E) elimination of the memorized template for songs sung the previous year.







Answer: A

Female spotted sandpipers aggressively court males and, after mating, leave the clutch of young for the male to incubate. This sequence may be repeated several times with different males until no available males remain, forcing the female to incubate her last clutch. Which of the following terms best describes this behavior?

Female spotted sandpipers aggressively court males and, after mating, leave the clutch of young for the male to incubate. This sequence may be repeated several times with different males until no available males remain, forcing the female to incubate her last clutch. Which of the following terms best describes this behavior? 

A) monogamy
B) polygyny
C) polyandry
D) promiscuity
E) certainty of paternity






Answer: C

According to Hamilton's rule,

According to Hamilton's rule, 

A) natural selection does not favor altruistic behavior that causes the death of the altruist.
B) natural selection favors altruistic acts when the resulting benefit to the beneficiary, corrected for relatedness, exceeds the cost to the altruist.
C) natural selection is more likely to favor altruistic behavior that benefits an offspring than altruistic behavior that benefits a sibling.
D) the effects of kin selection are larger than the effects of direct natural selection on individuals.
E) altruism is always reciprocal.







Answer: B

Which of the following is true of innate behaviors?

Which of the following is true of innate behaviors? 

A) Their expression is only weakly influenced by genes.
B) They occur with or without environmental stimuli.
C) They are limited to invertebrate animals.
D) They are expressed in most individuals in a population.
E) They occur in invertebrates and some vertebrates but not mammals.







Answer: D

Fred and Joe, two unrelated, mature male gorillas, encounter one another. Fred is courting a female. Fred grunts as Joe comes near. As Joe continues to advance, Fred begins drumming (pounding his chest) and bares his teeth. Joe then rolls on the ground on his back, gets up, and quickly leaves. This behavioral pattern is repeated several times during the mating season. Choose the most specific behavior described by this example.

Fred and Joe, two unrelated, mature male gorillas, encounter one another. Fred is courting a female. Fred grunts as Joe comes near. As Joe continues to advance, Fred begins drumming (pounding his chest) and bares his teeth. Joe then rolls on the ground on his back, gets up, and quickly leaves. This behavioral pattern is repeated several times during the mating season. Choose the most specific behavior described by this example. 

A) agonistic behavior
B) territorial behavior
C) learned behavior
D) social behavior
E) fixed action pattern






Answer: A

One way to understand how early environment influences differing behaviors in similar species is through the "cross-fostering" experimental technique. Suppose that the curly-whiskered mud rat differs from the bald mud rat in several ways, including being much more aggressive. How would you set up a cross-fostering experiment to determine if environment plays a role in the curly-whiskered mud rat's aggression?

One way to understand how early environment influences differing behaviors in similar species is through the "cross-fostering" experimental technique. Suppose that the curly-whiskered mud rat differs from the bald mud rat in several ways, including being much more aggressive. How would you set up a cross-fostering experiment to determine if environment plays a role in the curly-whiskered mud rat's aggression? 

A) You would cross curly-whiskered mud rats and bald mud rats and hand-rear the offspring to see if any grew up to be aggressive.
B) You would place newborn curly-whiskered mud rats with bald mud rat parents, place newborn bald mud rats with curly-whiskered mud rat parents, and let some mud rats of both species be raised by their own species. Then you would compare the outcomes.
C) You would remove the offspring of curly-whiskered mud rats and bald mud rats from their parents, raise them in the same environment, and then compare the outcomes.
D) You would see if curly-whiskered mud rats bred true for aggression.
E) You would replace normal newborn mud rats with deformed newborn mud rats to see if it triggered an altruistic response.





Answer: B

During a field trip, an instructor touched a moth resting on a tree trunk. The moth raised its forewings to reveal large eyespots on its hind wings. The instructor asked why the moth lifted its wings. One student answered that sensory receptors had fired and triggered a neuronal reflex culminating in the contraction of certain muscles. A second student responded that the behavior might frighten predators. Which statement best describes these explanations?

During a field trip, an instructor touched a moth resting on a tree trunk. The moth raised its forewings to reveal large eyespots on its hind wings. The instructor asked why the moth lifted its wings. One student answered that sensory receptors had fired and triggered a neuronal reflex culminating in the contraction of certain muscles. A second student responded that the behavior might frighten predators. Which statement best describes these explanations? 

A) The first explanation is correct, but the second is incorrect.
B) The first explanation refers to proximate causation, whereas the second refers to ultimate causation.
C) The first explanation is biological, whereas the second is philosophical.
D) The first explanation is testable as a scientific hypothesis, whereas the second is not.
E) Both explanations are reasonable and simply represent a difference of opinion.





Answer: B

The central concept of sociobiology is that

The central concept of sociobiology is that 

A) human behavior is rigidly predetermined.
B) the behavior of an individual cannot be modified.
C) human behavior consists mainly of fixed action patterns.
D) most aspects of our social behavior have an evolutionary basis.
E) the social behavior of humans is homologous to the social behavior of other social animals.







Answer: D

In Belding's ground squirrels, it is mostly the females that behave altruistically by sounding alarm calls. What is the likely reason for this distinction?

In Belding's ground squirrels, it is mostly the females that behave altruistically by sounding alarm calls. What is the likely reason for this distinction? 

A) Males have smaller vocal cords and are less likely to make sounds.
B) Females invest more in foraging and food stores, so they are more defensive.
C) Females settle in the area in which they were born, so the alarm is warning kin.
D) The sex ratio is biased.
E) Males forage in areas separate from females; therefore, alarm calls are useless.







Answer: C

The presence of altruistic behavior is most likely due to kin selection, a theory maintaining that

The presence of altruistic behavior is most likely due to kin selection, a theory maintaining that 

A) aggression between sexes promotes the survival of the fittest individuals.
B) genes enhance survival of copies of themselves by directing organisms to assist others who share those genes.
C) companionship is advantageous to animals because in the future they can help each other.
D) critical thinking abilities are normal traits for animals and they have arisen, like other traits, through natural selection.
E) natural selection has generally favored the evolution of exaggerated aggressive and submissive behaviors to resolve conflict without grave harm to participants.






Answer: B

Animals that help other animals of the same species

Animals that help other animals of the same species 

A) have excess energy reserves.
B) are bigger and stronger than the other animals.
C) are usually related to the other animals.
D) are always male.
E) have defective genes controlling their behavior.







Answer: C

Which of the following does not have a coefficient of relatedness of 0.5?

Which of the following does not have a coefficient of relatedness of 0.5? 

A) a father to his daughter
B) a mother to her son
C) an uncle to his nephew
D) a brother to his brother
E) a sister to her brother




Answer: C

How do altruistic behaviors arise through natural selection?

How do altruistic behaviors arise through natural selection? 

A) By his/her actions, the altruist increases the likelihood that some of its genes will be passed on to the next generation.
B) The altruist is appreciated by other members of the population because their survivability has been enhanced by virtue of his/her risky behavior.
C) Animals that perform altruistic acts are allowed by their population to breed more, thereby passing on their behavior genes to future generations.
D) Altruistic behaviors lower stress in populations, which increases the survivability of all the members of the population.
E) All of the options are correct.







Answer: A

Pair-bonding in a population of prairie voles can be prevented by

Pair-bonding in a population of prairie voles can be prevented by 

A) the ensuing confusion caused by introducing meadow voles.
B) administering a drug that inhibits the brain receptor for vasopressin in the CNS of males.
C) administering a drug that turns on ADH receptor sites in male voles.
D) dying the coat color from brown to blond in either male or female prairie voles.
E) allowing the population size to reach critically low levels.







Answer: B

The fru gene in fruit flies

The fru gene in fruit flies 

A) controls sex-specific development in the fruit fly.
B) is a master regulatory gene that directs expression of many other genes.
C) can be genetically manipulated in females so that they will perform male sex behaviors.
D) programs males for appropriate courtship behaviors.
E) All of the options are correct.






Answer: E

The color of throats of males in a population of side-blotched lizards is determined by

The color of throats of males in a population of side-blotched lizards is determined by 

A) the frequency of homozygous recessive genotype.
B) ambient temperature?blue = cold; orange = normal; yellow = hot.
C) stage of development/maturity.
D) their receptiveness to mate.
E) the success of the mating behavior of each of the throat color phenotypes.








Answer: E

Which of the following best describes "game theory" as it applies to animal behavior?

Which of the following best describes "game theory" as it applies to animal behavior? 

A) The fitness of a particular behavior is influenced by other behavioral phenotypes in a population.
B) The total of all of the behavioral displays, both male and female, is related to courtship.
C) An individual in a population changes a behavioral phenotype to gain a competitive advantage.
D) The play behavior performed by juveniles allows them to perfect adult behaviors that are needed for survival, such as hunting, courtship, and so on.
E) The evolutionary "game" is played between predator and prey, wherein the prey develops a behavior through natural selection that enables it to be less vulnerable to predation, and the predator counters with a new reciprocal predatory behavior.







Answer: A

Which of the following statements is true about certainty of paternity?

Which of the following statements is true about certainty of paternity? 

A) Young or eggs laid by a female are likely to contain the same genes as another female's eggs in a population of birds.
B) Certainty of paternity is high in most species with internal fertilization because the acts of mating and birth are separated by time.
C) Males that guard females they have mated with are certain of their paternity.
D) Certainty of paternity is low when egg laying and mating occur together, as in external fertilization.
E) Paternal behavior exists because it has been reinforced over generations by natural selection.







Answer: E