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Which of the following sensory receptors is incorrectly paired with its category?

rod-electromagnetic receptor
taste receptor-chemoreceptor
muscle spindle-mechanoreceptor
olfactory receptor-electromagnetic receptor
hair cell-mechanoreceptor

olfactory receptor-electromagnetic receptor

The middle ear converts

air pressure waves to fluid pressure waves.
fluid pressure waves to nerve impulses.
air pressure waves to nerve impulses.
fluid pressure waves to air pressure waves.
pressure waves to hair cell movements.

air pressure waves to fluid pressure waves.

During the contraction of a vertebrate skeletal muscle fiber, calcium ions

spread action potentials through the T tubules.
break cross-bridges by acting as a cofactor in the hydrolysis of ATP.
transmit action potentials from the motor neuron to the muscle fiber.
re-establish the polarization of the plasma membrane following an action potential.
bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed.

bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed.

Which sensory distinction is not encoded by a difference in neuron identity?

spicy and cool
red and green
salty and sweet
white and red
loud and faint

loud and faint

The transduction of sound waves into action potentials takes place

within the middle ear as the vibrations are amplified by the malleus, incus, and stapes.
as the basilar membrane vibrates at different frequencies in response to the varying volume of sounds.
as the basilar membrane becomes more permeable to sodium ions and depolarizes, initiating an action potential in a sensory neuron.
within the tectorial membrane as it is stimulated by the hair cells.
when hair cells are bent against the tectorial membrane, causing them to depolarize and release neurotransmitter that stimulates sensory neurons.

when hair cells are bent against the tectorial membrane, causing them to depolarize and release neurotransmitter that stimulates sensory neurons

Plasma membranes of adjacent cardiac muscle cells interlock at specialized regions called intercalated disks. What is the significance of this feature of cardiac muscles?

The intercalated disks play the same role as striations of skeletal muscle.
The intercalated disks generate action potentials within the heart muscle without nervous system input.
The intercalated disks allow coordinated contraction of the whole heart.

The intercalated disks allow coordinated contraction of the whole heart.

In mammals, the eardrum transmits sound waves to three small bones, which transmit the waves to fluid waves within the cochlea. Where are the three small bones located?

Middle ear
Outer ear
Inner ear

Middle ear

Identify the correct statement(s) about sensory receptors.
Select all that apply.

Mechanoreceptors detect sound.
Foods taste spicy when they activate the same sensory receptors that high temperatures activate.
Electromagnetic receptors detect pheromones.

Mechanoreceptors detect sound.
Foods taste spicy when they activate the same sensory receptors that high temperatures activate.

Sensory pathways have four basic functions: sensory reception, transduction, transmission, and perception. How do these functions differ between yourself and a star-nosed mole?
Select all that apply.
Select all that apply.
The perception of sensory input by humans and star-nosed moles differs.
The mechanism by which the energy of a sensory stimulus is transduced into a receptor potential differs between humans and star-nosed moles.
The number and type of sensory receptors in humans and star-nosed moles differ.

The perception of sensory input by humans and star-nosed moles differs.
The number and type of sensory receptors in humans and star-nosed moles differ.

Identify the role(s) of ATP in muscle contraction.
Select all that apply.

Provides the energy to convert myosin to a form that forms a cross-bridge with actin
Binds to myosin to break an actin-myosin cross-bridge
Binds to the troponin complex to expose myosin-binding sites

Provides the energy to convert myosin to a form that forms a cross-bridge with actin
Binds to myosin to break an actin-myosin cross-bridge

Which of the following is true of innate behaviors?

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

They are expressed in most individuals in a population

According to Hamilton's rule,

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

natural selection favors altruistic acts when the resulting benefit to the beneficiary, corrected for relatedness, exceeds the cost to the altruist.

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?

promiscuity
certainty of paternity
monogamy
polyandry
polygyny

polyandry

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

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

addition of new syllables to a canary's song repertoire.

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

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

the cultural tradition of using stones to crack nuts has arisen in only some populations.

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

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

In each individual, the form of the behavior is determined entirely by genes.

Graylag goslings imprint on a nearby object that moves away from them during a sensitive period in the first few hours after they hatch, and follow the object steadfastly from that time on. What is the adaptive value of this behavior?

This behavior is not adaptive because goslings may imprint on objects other than their parents.
This behavior is likely to increase gosling survival.
This behavior is genetic.

This behavior is likely to increase gosling survival.

A female zebra finch reared by a father with a red feather taped to his head will select a mate with a similar ornament over an unornamented male. What are plausible ultimate explanations for this behavior?
Select all that apply.

A female zebra finch that chooses a mate that resembles her father is more likely to choose a mate from her own species.
A female zebra finch learns to recognize suitable mates by observing her father.
Zebra finches are able to perceive ornamentation on other birds.

A female zebra finch that chooses a mate that resembles her father is more likely to choose a mate from her own species.

Select the correct statement(s) about the genetics of behavior.
Select all that apply.

Behaviors with a genetic component can evolve through natural selection.
Learned behaviors are not subject to genetic influence.
Most behavioral traits are determined by a single gene.

Behaviors with a genetic component can evolve through natural selection.

The majority of young, inexperienced Western garter snakes born in the laboratory from mothers captured in coastal areas of California readily eat pieces of slug. What are plausible proximate explanations for this behavior?
Select all that apply.

Coastal snakes can detect odor molecules produced by banana slugs.
Coastal snakes have a genetically acquired taste for banana slugs.
Coastal snakes that readily eat banana slugs gain most of their calories from this prey species.

Coastal snakes can detect odor molecules produced by banana slugs.
Coastal snakes have a genetically acquired taste for banana slugs.

In cross-fostering studies, the young of one species are placed in the care of adults from another species. In broad terms, what do researchers learn from such studies?
Select all that apply.

Changes in the behavior of cross-fostered young provide information about how the social and physical environment influences behavior.
Cross-fostering studies provide information about the relative importance of nature and nurture in the development of a trait.
Cross-fostering studies provide information about the evolutionary relationship between the two species.

Changes in the behavior of cross-fostered young provide information about how the social and physical environment influences behavior.
Cross-fostering studies provide information about the relative importance of nature and nurture in the development of a trait.

Which of the following areas of study focuses on the exchange of energy, organisms, and materials between ecosystems?

population ecology
organismal ecology
landscape ecology
community ecology
ecosystem ecology

landscape ecology

Which lake zone would be absent in a very shallow lake?

aphotic zone
pelagic zone
limnetic zone
littoral zone
benthic zone

aphotic zone

Which of the following is true with respect to oligotrophic lakes and eutrophic lakes?

Sediments in oligotrophic lakes contain larger amounts of decomposable organic matter.
Eutrophic lake water contains lower concentrations of nutrients.
Rates of photosynthesis are lower in eutrophic lakes.
Eutrophic lakes are richer in nutrients.
Oligotrophic lakes are more subject to oxygen depletion.

Eutrophic lakes are richer in nutrients.

Which of the following biomes is correctly paired with the description of its climate?

temperate broadleaf forest-relatively short growing season, mild winters
tundra-long summers, mild winters
temperate grasslands-relatively warm winters, most rainfall in summer
savanna-low temperature, precipitation uniform during the year
tropical forests-nearly constant day length and temperature

tropical forests-nearly constant day length and temperature

Which of the following is characteristic of most terrestrial biomes?

clear boundaries between adjacent biomes
a distribution predicted almost entirely by rock and soil patterns
annual average rainfall in excess of 250 cm
vegetation demonstrating vertical layering
cold winter months

vegetation demonstrating vertical layering

The oceans affect the biosphere in all of the following ways except

producing a substantial amount of the biosphere's oxygen.
moderating the climate of terrestrial biomes.
removing carbon dioxide from the atmosphere.
regulating the pH of freshwater biomes and terrestrial groundwater.
being the source of most of Earth's rainfall.

regulating the pH of freshwater biomes and terrestrial groundwater.

Which statement about dispersal is false?

Dispersal occurs only on an evolutionary time scale.
Colonization of devastated areas after floods or volcanic eruptions depends on dispersal.
Seeds are important dispersal stages in the life cycles of most flowering plants.
Dispersal is a common component of the life cycles of plants and animals.
The ability to disperse can expand the geographic distribution of a species.

Dispersal occurs only on an evolutionary time scale.

When climbing a mountain, we can observe transitions in biological communities that are analogous to the changes

in a community through different seasons.
in biomes at different latitudes.
in an ecosystem as it evolves over time.
at different depths in the ocean.
across the United States from east to west.

in biomes at different latitudes.

Suppose that the number of bird species is determined mainly by the number of vertical strata found in the environment. If so, in which of the following biomes would you find the greatest number of bird species?

savanna
tropical rain forest
temperate grassland
desert
temperate broadleaf forest

tropical rain forest

WHAT IF? If the direction of Earth's rotation reversed, the most predictable effect would be

winds blowing from west to east along the equator.
a loss of seasonal variation at high latitudes.
no more night and day.
a big change in the length of the year.
the elimination of ocean currents.

winds blowing from west to east along the equator.

In ecological terms, disturbance is an event such as a storm, fire, or human activity that changes a community, removing organisms and altering resource availability. Which of the following statements about the effects of disturbance is correct?

A healthy community is in an equilibrium state of balance, with few disturbances.
The effects of disturbance on a community are almost always negative.
Disturbances can create patches of different habitats in a community.

Disturbances can create patches of different habitats in a community.

Which statement accurately describes the potential effects of disturbance on species diversity?

Moderate levels of disturbance generally act to reduce species diversity within a community.
In many biomes, periodic disturbances may eliminate the dominant plants.
Many species are well adapted to survive periodic disturbances.

Many species are well adapted to survive periodic disturbances.

In Australia, researchers tested the hypothesis that sea urchin abundance limits kelp distribution. Select the evidence that offers the best support for this hypothesis.

There is an inverse relationship between the abundance of sea urchins and the abundance of kelp.
When sea urchins were removed from experimental plots, kelp cover increased.
Sea urchins graze on kelp.

When sea urchins were removed from experimental plots, kelp cover increased.

This graph shows the effect of removal of urchins and limpets (alone and together) on seaweed cover. Select the statement that accurately describes the results shown in this graph.

Sea urchins have a much greater effect than limpets in limiting seaweed cover.
Removing only limpets increased seaweed cover dramatically.
The lack of change over time in the control plots (with urchins and limpets present) shows that limpets and urchins have no effect on seaweed cover.

Sea urchins have a much greater effect than limpets in limiting seaweed cover.

Examine the climograph for some major North American biomes. Which two factors influence the distribution of organisms, as shown in this climograph?

The presence of tundra and presence of forested land
Annual mean temperature and annual mean precipitation
The presence of broadleaf and presence of coniferous forest

Annual mean temperature and annual mean precipitation

Population ecologists follow the fate of same-age cohorts to

determine if a population is regulated by density-dependent processes.
determine if a population's growth is cyclic.
determine the factors that regulate the size of a population.
determine the birth rate and death rate of each group in a population.
determine a population's carrying capacity.

determine the birth rate and death rate of each group in a population.

A population's carrying capacity

increases as the per capita growth rate (r) decreases.
generally remains constant over time.
can be accurately calculated using the logistic growth model.
may change as environmental conditions change.
can never be exceeded.

may change as environmental conditions change.

Scientific study of the population cycles of the snowshoe hare and its predator, the lynx, has revealed that

the hare population is r-selected and the lynx population is K-selected.
the prey population is controlled by predators alone.
both hare and lynx populations are regulated mainly by abiotic factors.
hares and lynx are so mutually dependent that each species cannot survive without the other.
multiple biotic and abiotic factors contribute to the cycling of the hare and lynx populations.

multiple biotic and abiotic factors contribute to the cycling of the hare and lynx populations

Based on current growth rates, Earth's human population in 2012 will be closest to

10 billion.
2 million.
7 billion.
3 billion.
4 billion.

7 billion.

A recent study of ecological footprints concluded that

it is not possible for technological improvements to increase Earth's carrying capacity for humans.
the ecological footprint of the United States is large because per capita resource use is high.
Earth's carrying capacity would increase if per capita meat consumption increased.
current demand by industrialized countries for resources is much smaller than the ecological footprint of those countries.
Earth's carrying capacity for humans is about 10 billion.

the ecological footprint of the United States is large because per capita resource use is high.

The observation that members of a population are uniformly distributed suggests that

the members of the population are competing for access to a resource.
the size of the area occupied by the population is increasing.
resources are distributed unevenly.
the members of the population are neither attracted to nor repelled by one another.
the density of the population is low.

the members of the population are competing for access to a resource.

According to the logistic growth equation

the birth rate (b) approaches zero as N approaches K.
the population grows exponentially when K is small.
population growth is zero when N equals K.
the number of individuals added per unit time is greatest when N is close to zero.
the per capita growth rate (r) increases as N approaches K.

population growth is zero when N equals K.

Which pair of terms most accurately describes life history traits for a stable population of wolves?

semelparous; r-selected
iteroparous; r-selected
iteroparous; K-selected
iteroparous; N-selected
semelparous; K-selected

iteroparous; K-selected

During exponential growth, a population always

quickly reaches its carrying capacity.
cycles through time.
grows at its maximum per capita rate.
loses some individuals to emigration.
grows by thousands of individuals.

grows at its maximum per capita rate.

Which of the following statements about human population in industrialized countries is incorrect?

The survivorship curve is Type I.
Average family size is relatively small.
Age distribution is relatively uniform.
The population has undergone the demographic transition.
Life history is r-selected.

Life history is r-selected.

Consider a population whose growth over a given time period can be described by the exponential model: dN/dt = rN. Select the correct statement about this population.

A population with an r of 0 will have no births or deaths during the time period under consideration.
A population with a positive value of r will grow exponentially.
A population with an r of 0.1 will decrease over time.

A population with a positive value of r will grow exponentially.

Consider a population whose growth can be described by the logistic growth model: dN/dt = rmaxN[(K − N)/K]. Which of the following statements about this population is true?

rmax declines as N increases.
At low values of N, the logistic growth and exponential growth (dN/dt = rN) models predict similar population growth.
K is a constant value.

At low values of N, the logistic growth and exponential growth (dN/dt = rN) models predict similar population growth.

The graph shows the growth of a laboratory culture of Paramecium aurelia. After 15 days, the researcher removed ~400 paramecia from the culture. How will the population growth rate (dN/dt) change as a result of this action?

The growth rate of the Paramecium population will decrease.
The growth rate of the Paramecium population will increase.
The growth rate of the Paramecium population will not change.

The growth rate of the Paramecium population will increase.

Select the correct statement about the global carrying capacity for the human population.

The global carrying capacity for the human population is limitless because technological advances allow food supply to keep up with global population growth.
Estimates of the global carrying capacity for the human population depend on resource use per capita.
It is impossible to calculate the global carrying capacity for the human population.

Estimates of the global carrying capacity for the human population depend on resource use per capita.

Select the correct statement about the factors that limit the growth of a population.

Density-dependent factors are biotic; density-independent factors are abiotic.
The most important factor limiting population growth is the scarcest factor in that area.
If a factor limits population growth, increasing its availability will increase population growth.

If a factor limits population growth, increasing its availability will increase population growth.

The feeding relationships among the species in a community determine the community's

species richness.
secondary succession.
trophic structure.
species-area curve.
ecological niche.

trophic structure

The principle of competitive exclusion states that

two species cannot coexist in the same habitat.
two species that have exactly the same niche cannot coexist in a community.
competition between two species always causes extinction or emigration of one species.
competition in a population promotes survival of the best-adapted individuals.
two species will stop reproducing until one species leaves the habitat.

two species that have exactly the same niche cannot coexist in a community.

Based on the intermediate disturbance hypothesis, a community's species diversity is increased by

frequent massive disturbance.
intensive disturbance by humans.
stable conditions with no disturbance.
human intervention to eliminate disturbance.
moderate levels of disturbance.

moderate levels of disturbance.

According to the equilibrium model of island biogeography, species richness would be greatest on an island that is

environmentally homogeneous.
small and remote.
large and close to a mainland.
small and close to a mainland.
large and remote.

large and close to a mainland.

Keystone predators can maintain species diversity in a community if they

prey on the community's dominant species.
allow immigration of other predators.
reduce the number of disruptions in the community.
prey only on the least abundant species in the community.
competitively exclude other predators.

prey on the community's dominant species.

Food chains are sometimes short because

most producers are inedible.
most of the energy in a trophic level is lost as it passes to the next higher level.
predator species tend to be less diverse and less abundant than prey species.
local extinction of a species causes extinction of the other species in its food chain.
only a single species of herbivore feeds on each plant species.

most of the energy in a trophic level is lost as it passes to the next higher level.

Which of the following could qualify as a top-down control on a grassland community?

limitation of plant biomass by rainfall amount
effect of humidity on plant growth rates
effect of grazing intensity by bison on plant species diversity
influence of temperature on competition among plants
influence of soil nutrients on the abundance of grasses versus wildflowers

effect of grazing intensity by bison on plant species diversity

The most plausible hypothesis to explain why species richness is higher in tropical than in temperate regions is that

tropical communities are younger.
tropical regions have very high rates of immigration and very low rates of extinction.
diversity increases as evapotranspiration decreases.
higher temperatures cause more rapid speciation.
tropical regions generally have more available water and higher levels of solar radiation.

tropical regions generally have more available water and higher levels of solar radiation.

Select the correct statement(s) about a terrestrial food chain.
Select all that apply.

The total biomass of the top trophic level is greatest because the top consumers are large.
About 1% of the energy stored in producers is converted to organic matter at the secondary consumer level.
Energy is transferred from decomposers to plants to herbivores to carnivores.

About 1% of the energy stored in producers is converted to organic matter at the secondary consumer level.

Gray wolves, once the top predators in Yellowstone National Park, were hunted to extinction there in 1926. In 1995, 15 wolves were brought to Yellowstone from Alberta. The wolf population has now grown to 300.
The forest community in Yellowstone National Park can be described by a top-down model of community organization. Wolves hunt and eat elk. Elk are herbivores that prefer riparian vegetation (plants growing next to streams and lakes). Ravens, bears, and eagles feed on elk carcasses.
How would you expect the return of the wolves to Yellowstone to affect the other species there?
Select all that apply.

Riparian vegetation would decline.
Elk populations would decline.
Bear populations would decline.

Elk populations would decline.

What is a likely outcome of a moderate disturbance, such as a severe thunderstorm?
Select all that apply.

Reduced species diversity within a community
Patches of different habitats within the landscape
Loss of an equilibrium state of balance, leading to a less healthy community

Patches of different habitats within the landscape

Select the correct statement(s) about the transfer of food energy up the trophic levels from its source in autotrophs.
Select all that apply.

Few plants have adaptations to reduce feeding by herbivores.
The length of a food chain is limited by the inefficiency of energy transfer along the chain.
An organism feeds at only one trophic level.

The length of a food chain is limited by the inefficiency of energy transfer along the chain

Which of the following may result from resource partitioning?
Select all that apply.

A population's fundamental niche may be smaller than its realized niche.
A population may have a smaller realized niche when it coexists with a competitor.
Competing species may partition time, feeding at different times of day.

A population may have a smaller realized niche when it coexists with a competitor.
Competing species may partition time, feeding at different times of day.

Which of the following organisms is incorrectly paired with its trophic level?

eagle-tertiary consumer
fungus-detritivore
cyanobacterium-primary producer
zooplankton-primary producer
grasshopper-primary consumer

zooplankton-primary producer

Which of these ecosystems has the lowest net primary production per square meter?

a tropical rain forest
a salt marsh
an open ocean
a grassland
a coral reef

an open ocean

The discipline that applies ecological principles to returning degraded ecosystems to a more natural state is known as

conservation ecology.
population viability analysis.
restoration ecology.
resource conservation.
landscape ecology.

restoration ecology.

Nitrifying bacteria participate in the nitrogen cycle mainly by

incorporating nitrogen into amino acids and organic compounds.
converting ammonia to nitrogen gas, which returns to the atmosphere.
converting nitrogen gas to ammonia.
converting ammonium to nitrate, which plants absorb.
releasing ammonium from organic compounds, thus returning it to the soil.

converting ammonium to nitrate, which plants absorb.

Which of the following has the greatest effect on the rate of chemical cycling in an ecosystem?

the production efficiency of the ecosystem's consumers
the trophic efficiency of the ecosystem
the location of the nutrient reservoirs in the ecosystem
the rate of decomposition in the ecosystem
the ecosystem's rate of primary production

the rate of decomposition in the ecosystem

The Hubbard Brook watershed deforestation experiment yielded all of the following results except:

Calcium levels remained high in the soil of deforested areas.
The flow of minerals out of a natural watershed was offset by minerals flowing in.
Deforestation increased water runoff.
Most minerals were recycled within a forest ecosystem.
The nitrate concentration in waters draining the deforested area became dangerously high.

Calcium levels remained high in the soil of deforested areas.

Which of the following would be considered an example of bioremediation?

reconfiguring the channel of a river
using a bulldozer to regrade a strip mine
adding seeds of a chromium-accumulating plant to soil contaminated by chromium
dredging a river bottom to remove contaminated sediments
adding nitrogen-fixing microorganisms to a degraded ecosystem to increase nitrogen availability

adding nitrogen-fixing microorganisms to a degraded ecosystem to increase nitrogen availability

If you applied a fungicide to a cornfield, what would you expect to happen to the rate of decomposition and net ecosystem production (NEP)?

Decomposition rate would decrease and NEP would increase.
Decomposition rate would increase and NEP would decrease.
Neither would change.
Both decomposition rate and NEP would increase.
Both decomposition rate and NEP would decrease.

Decomposition rate would decrease and NEP would increase.

How do pyramids of net production and pyramids of biomass differ?

Pyramids of net production include fewer trophic levels than pyramids of biomass.
Unlike pyramids of biomass, pyramids of net production are based on measurements per unit time.
Unlike pyramids of net production, the shape of a pyramid of biomass varies with the size of the organisms in the ecosystem.

Unlike pyramids of biomass, pyramids of net production are based on measurements per unit time.

Some aquatic ecosystems have inverted biomass pyramids, in which primary consumers outweigh the producers. Why is it that a pyramid of biomass, but not a pyramid of net production, may be inverted?

A pyramid of biomass may be inverted because it is based on biomass at one point in time. Pyramids of net production are based on productivity per unit time.
A pyramid of biomass may be inverted when the producers (e.g., phytoplankton) are much more plentiful than the consumers (e.g., zooplankton). Producers are always outnumbered by consumers, so pyramids of net production are never inverted.
A pyramid of biomass may be inverted when the producers (e.g., phytoplankton) are much smaller than the consumers (e.g., zooplankton). Producers always have higher productivity than consumers, so pyramids of net production are never inverted.

A pyramid of biomass may be inverted because it is based on biomass at one point in time. Pyramids of net production are based on productivity per unit time.

Why is it that nitrogen is often a limiting plant nutrient, despite the fact that the atmosphere is 80% nitrogen gas (N2)?

Because plants cannot assimilate nitrogen-containing compounds
Because N2 easily leaches away from soil
Because plants cannot fix N2

Because plants cannot fix N2

Select the correct statement describing the nitrogen cycle.

Nitrogen-fixing microbes provide energy for carbon fixation.
Denitrifying bacteria reduce ammonia (NH3 +) to molecular nitrogen (N2).
Bacteria obtain energy from nitrification.

Bacteria obtain energy from nitrification.

Your textbook states, "Like organisms, ecosystems are open systems." Which of the following provide a legitimate example to illustrate this statement?
Select all that apply.

A population of reef fishes with a high reproductive rate in a mangrove ecosystem may be a source of recruits for a population in an adjacent coral reef ecosystem with a lower reproductive rate.
Detritivores in soil consume nonliving organic matter and make the nutrients available to plants.
Earth's atmosphere is bombarded by about 1022 joules of solar radiation each day.

A population of reef fishes with a high reproductive rate in a mangrove ecosystem may be a source of recruits for a population in an adjacent coral reef ecosystem with a lower reproductive rate.
Earth's atmosphere is bombarded by about 1022 joules of solar radiation each day.

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