Deck 25: Global Ecology

Question 1

The largest pool of carbon can be found in

A) the atmosphere.
B) sediments and rocks.
C) land surface, including soils and vegetation.
D) oceans.

Answer 1

B

Question 2

Which statement regarding the oceanic pool of carbon is false?

A) Most of the carbon is found in the deeper waters.
B) There is relatively little mixing between the ocean surface and the deeper waters.
C) CO₂ dissolves in water due to a concentration gradient between the atmosphere (high concentration) and the ocean (low concentration).
D) The oceanic pool is the most stable of the major pools.

Answer 2

D

Question 3

The concentration of atmospheric carbon dioxide in 2016 was approximately _______ parts per _______.

A) 290; billion
B) 390; billion
C) 390; million
D) 404; million

Answer 3

D

Question 4

Why is there a net flow of carbon from the atmosphere to the oceans?

A) The lower concentration of carbon dioxide in the oceans compared to the atmosphere leads to carbon dioxide diffusing into the oceans.
B) Plankton at the surface funnel carbon from the atmosphere to the ocean.
C) Carbon dioxide dissolves more readily in water than in the atmosphere.
D) Respiration from aquatic life lowers the carbon dioxide concentration in the oceans.

Question 5

Refer to the figure.
The figure shows the temperature (in °C, relative to modern temperature) and the concentrations of carbon dioxide (in ppm) and methane (in ppb) over the past 400,000 years.

- The current concentration of carbon dioxide is 404 ppm (not shown on the figure). Use the data in the figure to determine the highest carbon dioxide concentration levels that occurred over the past 400,000 years. At that point, the concentration of carbon dioxide was about _______% of the current concentration.

A) 45?50
B) 55?60
C) 70?75
D) 90?95

Question 6

Refer to the figure.
The figure shows the temperature (in °C, relative to modern temperature) and the concentrations of carbon dioxide (in ppm) and methane (in ppb) over the past 400,000 years.

-According to various lines of evidence, our species emerged about 160,000 years ago. At that time, temperatures were about _______°C cooler than they are now, and the carbon dioxide level was about _______ ppm.

A) 4; 200
B) 4; 300
C) 8; 200
D) 8; 300

Question 7

Refer to the figure.
The figure shows the temperature (in °C, relative to modern temperature) and the concentrations of carbon dioxide (in ppm) and methane (in ppb) over the past 400,000 years.

- Ten thousand years ago, the concentration of carbon dioxide was about _______ times that of methane.

A) 5
B) 20
C) 50
D) 500

Question 8

Refer to the figure.
The figure shows the temperature (in °C, relative to modern temperature) and the concentrations of carbon dioxide (in ppm) and methane (in ppb) over the past 400,000 years.

-Relative to the average over the last 400,000 years, concentrations of CO₂ during the warm interglacial periods in this time period have been _______, and concentrations of methane have been _______.

A) high; high
B) high; low
C) low; high
D) low; low

Question 9

Which statement about the nitrogen cycle is false?

A) The nitrogen cycle is not linked to the carbon cycle.
B) Atmospheric nitrogen exists primarily in the unreactive dinitrogen gas form.
C) Despite their relatively small size, land and ocean surface pools of nitrogen have very high biological activity.
D) Human activities have greatly altered the global nitrogen cycle.

Question 10

Which statement about the global phosphorus cycle is true?

A) It has a large atmospheric pool.
B) Because of the relatively high metabolic demand for phosphorus in the fixation of nitrogen gas, the rate of the nitrogen cycle is influenced by the availability of phosphorus.
C) Only a small fraction of the phosphorus transported from aquatic to terrestrial ecosystems is deposited in deep ocean sediments and lost.
D) The smallest pools of terrestrial phosphorus are found in soils.

Question 11

Which statement best describes the effect of occlusion of phosphorus in soils on the flux of anthropogenic phosphorus from terrestrial to aquatic ecosystems?

A) It always accelerates the flux.
B) It minimizes the flux, but that flux still has significant potential for negative environmental effects.
C) It accelerates the flux when nitrogenous compounds are abundant but has little or no effect otherwise.
D) It has minimized the flux to the extent that the flux does not have significant potential for negative environmental effects.

Question 12

Which statement about the global sulfur cycle is false?

A) On a time scale of centuries, volcanic eruptions and dust from bare soils each account for approximately the same amount of sulfur that it is emitted into the atmosphere.
B) Sulfur is often a limiting factor for organismal growth.
C) Anthropogenic changes to the sulfur cycle have resulted in an increase in the pH of precipitation.
D) The major global pools are in terrestrial soils.

Question 13

Refer to the figure.
This figure is of the global carbon cycle. (Note: Boxes represent major pools of C, measured in petagrams [1 Pg = 10¹⁵ g]. Arrows represent major fluxes of C, measured in Pg per year; anthropogenic fluxes are shown in orange.)What is the net flux of carbon to the atmosphere?

A) ‒4 Pg
B) 1.7 Pg
C) 6.4 Pg
D) 8.7 Pg

Question 14

Which statement best describes our current understanding of the relationship between CO₂ levels and photosynthetic activity?

A) Increasing CO₂ levels will result in a sustained increase in photosynthetic activity in both herbaceous plants and forest trees.
B) Increasing CO₂ levels will result in a sustained decrease in photosynthetic activity in both herbaceous plants and forest trees.
C) Increases in photosynthesis rates due to increases in CO₂ levels are likely to be short-lived for some herbaceous plants, but may be more sustainable for forest trees.
D) Increases in photosynthesis rates due to increases in CO₂ levels are likely to be short-lived for forest trees, but may be more sustainable for some herbaceous plants.

Question 15

DeLucia and colleagues have shown that increasing carbon dioxide has led to increased NPP in a pine forest. If this result can be generalized, it suggests that forests could be a _______ of anthropogenic carbon and thus tend to _______ the greenhouse effect.

A) source; worsen
B) source; offset
C) sink; worsen
D) sink; offset

Question 16

In the absence of human activity, the net flux would be _______ Pg.

A) ‒4
B) ‒3
C) 1.7
D) 4.7

Question 17

Before the Industrial Revolution, the flux of carbon from the terrestrial to the atmospheric pools _______ the flux in the opposite direction. Today, the flux of carbon from the terrestrial to atmospheric pools _______ the flux in the opposite direction.

A) exceeded; exceeds
B) exceeded; is about equal to
C) was about equal to; exceeds
D) was about equal to; is less than

Question 18

Which statement about deforestation is false?

A) Before the mid-nineteenth century, the largest anthropogenic release of carbon into the atmosphere occurred via forest clearing.
B) Currently deforestation accounts for a negligible amount (less than 2%) of the anthropogenic release of carbon into the atmosphere.
C) Burning of forests releases CO₂ as well as accelerating decomposition rates in forest soils.
D) Currently most deforestation is occurring in the tropics.

Question 19

Increasing levels of carbon dioxide in oceans makes them _______ acidic. This change affects the ability of marine organisms to form protective shells made up of _______ carbonate.

A) more; phosphorus
B) more; calcium
C) more; magnesium
D) less; calcium

Question 20

Refer to the figure.
This figure shows spatial patterns of N deposition in Great Britain. What is the most likely change in carbon cycling in Great Britain as a result of changes in N cycling?

A) Increases in net primary production in northern Great Britain
B) Increases in net primary production in western Great Britain
C) Decreases in net primary production in southeastern Great Britain due to nitrogen saturation
D) Eutrophication and increased aquatic productivity in northern Great Britain

Question 21

Which statement about methane and global warming is false?

A) On a per molecule basis, methane is a more potent greenhouse gas than carbon dioxide.
B) Livestock production contributes to methane emissions.
C) Atmospheric methane concentrations are much higher than they were before the industrial revolution.
D) Methane emissions are caused only by anthropogenic factors.

Question 22

Aerosols are known to have a _______ effect on global temperatures. Some types of aerosols have increased in concentration recently, while others have decreased. One type of aerosol that has increased in concentration is the one associated with _______.

A) warming; dust due to desertification
B) warming; increasing volcanic eruptions
C) cooling; dust due to desertification
D) cooling; anthropogenic nitrous oxide emissions

Question 23

Which statement about climate is false?

A) Climate is the long-term description of weather, and encompasses not just average conditions but also the full scope of variation.
B) Climatic variation can occur only on very long time scales.
C) Changes in climate can have profound effects on ecological patterns and processes.
D) Climatic change refers to directional change in climate over a period of several decades.

Question 24

Between 1880 and 2012, the average annual global surface temperature

A) decreased 0.8°C.
B) increased 0.2°C.
C) increased 0.8°C.
D) increased 2.0°C.

Question 25

The warming of Earth in recent decades has been most pronounced in

A) and near Antarctica.
B) the tropics, just south of the equator.
C) the tropics, just north of the equator.
D) the mid-to-high latitudes of the Northern Hemisphere.

Question 26

Refer to the figure.
The figure shows mean annual global temperature anomalies between 1880 and 2019.

-Prior to 1970, over which 20-year period did the global temperature rise the most?

A) 1881-1900
B) 1901-1920
C) 1921-1940
D) 1941-1960

Question 27

Refer to the figure.
The figure shows mean annual global temperature anomalies between 1880 and 2019.

-
Between 2000 and 2019, temperatures

A) decreased 0.10°C.
B) increased 0.05°C.
C) increased 0.12°C.
D) increased 0.30°C.

Question 28

Select the greenhouse gas that fits the following description: Its concentration in the atmosphere has increased substantially over the last century, and while its total contribution to the greenhouse effect is only about 30% that of CO₂, its contribution on a per molecule basis is greater than that of CO₂.

A) Water vapor
B) Sulfur dioxide
C) Methane
D) Nitrous oxide

Question 29

A reduction in aerosols in the atmosphere would tend to _______ temperatures, because aerosols _______ sunlight.

A) increase; reflect
B) increase; absorb
C) decrease; reflect
D) None of the above; a change in aerosol concentrations should not result in detectable climate change.

Question 30

Which event would lead to enhanced atmospheric warming?

A) Decreased anthropogenic emissions of SO₂
B) Increased dust in association with land use change and desertification
C) A major volcanic eruption
D) Reforestation of temperate farmlands

Question 31

Refer to the figure.
Computer models observed global temperature changes with and without anthropogenic forces, proving that humans have indeed played a major role in observed warming. Using the figure, what year did anthropogenic factors start making a significant impact?

A) 1910
B) 1975
C) 1990
D) 2010

Question 32

Which organism would most likely encounter the greatest difficulty in responding to climate change?

A) A butterfly
B) A biennial shrub with animal-dispersed seeds
C) A long-lived tree
D) A rodent

Question 33

Which of the following is not one of the currently documented ecological responses to climate change?

A) Many species of nonmigratory European butterflies have shifted their ranges northward, with few shifting southward.
B) Migratory birds in England and North America have been arriving at nest sites later in the season.
C) There has been an upward shift from lower elevations to higher elevations of vascular plants in the European Alps.
D) Lizard populations have been going extinct.

Question 34

According to the studies of Nemani and colleagues, global NPP _______ during the study period (1982-1999), with the largest increase documented in the _______.

A) increased; tropics
B) increased; northern latitudes
C) decreased; southern latitudes
D) decreased; tropics

Question 35

Refer to the figure.
Individual species vary in their response to climate change. What is the best explanation for what is happening to communities in the European Alps as a result of climate change?

A) On mountains with elevations lower than 3,200 feet, existing communities are becoming more species-rich due to the addition of low-elevation species.
B) On mountains with elevations higher than 3,200 feet, existing communities are being displaced by lower-elevation communities.
C) Across all mountains, species richness is increasing because of subalpine species migrating into the alpine.
D) The species richness of the communities with the most historical species richness are increasing the most because they were historically the most resource-rich communities.

Question 36

Refer to the figure.


- This vegetation reconstruction shows major shifts in plant communities since the last glacial maximum 18,000 years ago. Why was there so much "No analog" community for much of the past 18,000 years?

A) Species were evolving in response to changes in climate.
B) Thermal tolerance between plant species produced novel communities.
C) Unique climate conditions during the transition from the last glacial maxima produce unique plant communities.
D) Dispersal ability in response to a changing environment produced novel communities.

Question 37

Refer to the figure.


- Large-scale community changes observed historically took thousands of years. For example, it took from 18,000 years ago to 6,000 years ago for forest tundra to reach even a portion of its current geographical location. Which factor will increase the susceptibility of species to extinction due to our current, rapidly changing environment that was not present historically?

A) Assisted migration by humans
B) Habitat fragmentation
C) Development of novel communities
D) Accelerated evolutionary changes

Question 38

In areas such as Vermont that have a seasonal snowpack, which of the following would likely be the most acidic?

A) Precipitation that falls in late autumn
B) Snow that falls in December
C) The first meltwater of spring
D) Rains in May

Question 39

Advanced stages of soil acidification lead to the release from cation exchange sites of _______ ions, which are toxic to plant roots and animals.

A) aluminum
B) calcium
C) magnesium
D) potassium

Question 40

Refer to the figure.
The figure shows the pH of precipitation in the United States in 1990 (left) and 2017 (right). The acidity of precipitation during both time periods was most extreme in the _______ part of the country, and the acidity of precipitation in this area _______ between 1994 and 2004.

A) eastern; increased
B) eastern; decreased
C) western; increased
D) western; did not change

Question 41

As nitrogen input increases, _______ remains nearly constant at first and then increases rapidly at higher levels of nitrogen input.

A) nitrogen mineralization
B) net primary productivity
C) leaf nitrogen concentration
D) NO₃^- leaching and soil acidification

Question 42

In eutrophic waters, algal growth is _______, leading to _______ decomposition rates and thus _______ levels of oxygen.

A) increased; higher; higher
B) increased; higher; lower
C) increased; lower; lower
D) decreased; higher; higher

Question 43

Refer to the figure.
Which figure, based on the studies of grassland communities by Stevens, best describes the relationship of species diversity to varying levels of deposition of inorganic nitrogen?

A) Figure A
B) Figure B
C) Figure C
D) Figure D

Question 44

Ozone in the _______ is beneficial because it acts as a shield that blocks mainly _______ radiation.

A) stratosphere; infrared
B) stratosphere; ultraviolet-B
C) trophosphere; infrared
D) trophosphere; ultraviolet-B

Question 45

Loss of stratospheric ozone has been most pronounced in

A) the Arctic.
B) Northern Hemisphere temperate zones.
C) the tropics.
D) the Antarctic.

Question 46

Which statement about CFCs is false?

A) They are largely inert in the stratosphere; their negative effect on ozone occurs because they react with other chemicals in the trophosphere to produce reactive chlorine molecules that destroy ozone.
B) They were originally developed for use as refrigerants.
C) They are not the only anthropogenic chemical that can destroy ozone.
D) Their atmospheric concentrations have been decreasing in recent years.

Question 47

The potential for harmful effects from the loss of the shielding benefits of ozone is strongest

A) at low elevations.
B) in the tropics.
C) at high latitudes.
D) in coastal ecosystems.

Question 48

Ozone in the _______ acts as a shield protecting Earth's surface from UV radiation. Ozone in the _______ is harmful to organisms.

A) troposphere; stratosphere
B) troposphere; mesosphere
C) stratosphere; thermosphere
D) stratosphere; troposphere

Question 49

Which statement about ozone in the lower atmosphere is false?

A) It is a greenhouse gas.
B) It can cause respiratory damage in humans.
C) It can damage the membranes of plants, thus potentially reducing their photosynthetic capacity.
D) It is not produced naturally and results only from anthropogenic activity.

Question 50

Some of the more radical proposals to address and mitigate climate change involve geoengineering, which involves deliberately modifying Earth's climate. Evaluate how the options listed would affect the global climate and global biogeochemical cycles by answering the question that follows.
Option 1: Plant more trees.
Option 2: Build one or more giant reflective mirrors and send them into Earth's orbit.
Option 3: Fertilize ocean water with iron.
Option 4: Spray sulfuric acid as aerosol into the stratosphere.

-
Describe two ways that option 1 would affect the carbon cycle.

Question 51

Some of the more radical proposals to address and mitigate climate change involve geoengineering, which involves deliberately modifying Earth's climate. Evaluate how the actions listed would affect the global climate and global biogeochemical cycles by answering the questions that follow.
Option 1: Plant more trees.
Option 2: Build one or more giant reflective mirrors and send them into Earth's orbit.
Option 3: Fertilize ocean water with iron.
Option 4: Spray sulfuric acid as aerosol into the stratosphere.

-
Based only on its effect on the carbon cycle, how would you expect option 1 to impact the global climate? How long would it take for the effects to be seen? How long would you expect these effects to last? What potential problems are there with this option?

Question 52

Some of the more radical proposals to address and mitigate climate change involve geoengineering, which involves deliberately modifying Earth's climate. Evaluate how the actions listed would affect the global climate and global biogeochemical cycles by answering the questions that follow.
Option 1: Plant more trees.
Option 2: Build one or more giant reflective mirrors and send them into Earth's orbit.
Option 3: Fertilize ocean water with iron.
Option 4: Spray sulfuric acid as aerosol into the stratosphere.

-
How would option 2 (reflective mirrors) function to change the global climate? What effect would this option have on the global climate? How long would it take for the effects on global climate to be seen? How long would you expect these effects to last? What are potential problems with this option?

Question 53

Some of the more radical proposals to address and mitigate climate change involve geoengineering, which involves deliberately modifying Earth's climate. Evaluate how the actions listed would affect the global climate and global biogeochemical cycles by answering the questions that follow.
Option 1: Plant more trees.
Option 2: Build one or more giant reflective mirrors and send them into Earth's orbit.
Option 3: Fertilize ocean water with iron.
Option 4: Spray sulfuric acid as aerosol into the stratosphere.

-
What effect would option 3 (fertilizing ocean with iron) have on the carbon cycle? What outcome would create the carbon sink? Based on its effect on the carbon cycle, how would you expect option 3 to impact the global climate? What additional abiotic factor might limit the effectiveness of this option, and why? How would this additional factor influence your decision on when to implement this option?

Question 54

Some of the more radical proposals to address and mitigate climate change involve geoengineering, which involves deliberately modifying Earth's climate. Evaluate how the actions listed would affect the global climate and global biogeochemical cycles by answering the questions that follow.
Option 1: Plant more trees.
Option 2: Build one or more giant reflective mirrors and send them into Earth's orbit.
Option 3: Fertilize ocean water with iron.
Option 4: Spray sulfuric acid as aerosol into the stratosphere.

-
How would option 4 (spray sulfuric acid into the stratosphere) affect global climate? What effect would it have on greenhouse gas levels in the atmosphere? What effect would option 4 have on the sulfur cycle? What is a potential negative effect of this option?

Question 55

Some of the more radical proposals to address and mitigate climate change involve geoengineering, which involves deliberately modifying Earth's climate. Evaluate how the actions listed would affect the global climate and global biogeochemical cycles by answering the questions that follow.
Option 1: Plant more trees.
Option 2: Build one or more giant reflective mirrors and send them into Earth's orbit.
Option 3: Fertilize ocean water with iron.
Option 4: Spray sulfuric acid as aerosol into the stratosphere.

-
Classify options 1-4 into two groups, based on the mechanisms by which they mitigate climate change. Which options would be most effective in changing atmospheric composition? Which options would be most effective in combating acid rain and ocean acidification?

Question 56

Some of the more radical proposals to address and mitigate climate change involve geoengineering, which involves deliberately modifying Earth's climate. Evaluate how the actions listed would affect the global climate and global biogeochemical cycles by answering the questions that follow.
Option 1: Plant more trees.
Option 2: Build one or more giant reflective mirrors and send them into Earth's orbit.
Option 3: Fertilize ocean water with iron.
Option 4: Spray sulfuric acid as aerosol into the stratosphere.

-
Suppose global temperature suddenly increases by 4°C. If this sudden increase imperiled many of the species on Earth, which of the four options would decrease global temperatures most quickly and be easiest to implement on short notice?

Question 57

Refer to the figure.
Figure 1
Suppose a researcher is experimenting with an invention that might affect global climate. This researcher builds a model to predict how the invention might impact global temperatures and global atmospheric composition over time. The results of the model are shown in Figure 1.

-Based on the predictions of the model, answer the following questions:
a) How will the invention affect global temperatures?
b) How will the invention affect global atmospheric composition?
c) Based on the data, does this invention remove CO₂ or block sunlight?

Question 58

Refer to the figure.
Figure 1
Suppose a researcher is experimenting with an invention that might affect global climate. This researcher builds a model to predict how the invention might impact global temperatures and global atmospheric composition over time. The results of the model are shown in Figure 1.

- Based on the predictions of the model, answer the following questions:
a) How would you expect this mechanism and its impact on climate to affect ecological responses to climate change?
b) Would you expect biological communities to return to pre-warming locations and pre-warming compositions?

Question 59

Refer to the figure.
Figure 2
Suppose you are studying an ecological community on a mountain. The mountain has a high summit and a gradual slope. Temperatures are warm at the base of the mountain, and become increasingly cooler towards the summit, as shown in Figure 2.Answer the following questions:
a) What is the temperature difference between the base of the mountain and the summit?
b) Suppose average temperatures increase 2°C. Add a line to the graph in Figure 2 (this will be referred to as Figure 3) to indicate the new temperature at each elevation.
c) Suppose a tree species thrives between 13°C and 17°C. At what elevation would you expect to find the tree under normal temperatures? At what elevation would you expect to find the tree following the 2°C warming?
d) How do you expect the range size of the tree to change due to the change in temperature? Why?

Question 60

Anthropogenic release of carbon has primarily been from the _______ pool to the _______ pool.

A) oceanic; atmospheric
B) oceanic; terrestrial
C) terrestrial; atmospheric
D) terrestrial; oceanic

Question 61

Refer to the figure.
Which figure best describes the relationship between carbon intake in oceans and pH of the oceans?

A) Figure A
B) Figure B
C) Figure C
D) Figure D

Question 62

Refer to the figure.
Based on the figure, N fixation by industrial methods accounts for _______% of the total fixation of N.

A) 27
B) 44
C) 52
D) 73

Question 63

Which statement about sulfur is false?

A) Sulfur is often a limiting factor for organismal growth.
B) On a time scale of centuries, volcanic eruptions and dust from bare soils each account for approximately the same amount of sulfur that is emitted into the atmosphere.
C) Most of the anthropogenic emissions of sulfur come from the burning of coal and oil and the refining of ore from mining.
D) One negative consequence of the anthropogenic changes to the sulfur cycle is increased acidity of rain.

Question 64

Select the greenhouse gas that fits the following description: It is the largest contributor to greenhouse warming. Over the course of human history, its concentration in the atmosphere has not changed much, but it varies considerably from place to place.

A) Carbon dioxide
B) Water vapor
C) Nitrous oxide
D) Methane

Question 65

Dust from the Gobi Desert can cross the Pacific Ocean and fall on the remote, tropical oceanic islands of Hawaii. What direct impact will this dust most likely have on nutrient cycling in the terrestrial ecosystems of Hawaii?

A) Increased net primary production due to phosphorus addition
B) Increased temperature and higher rates of nitrogen mineralization because of changes in albedo
C) Reduced net primary production due to reduced sunlight
D) Increased net primary production due to iron addition

Question 66

Refer to the map.
The map shows the temperature change in °C across different regions of the globe from the averages of 1901‒2012. According to the map, how much warmer is Paris in 2012 than in 1901?

A) 0.2 °C
B) 0.8 °C
C) 1.5 °C
D) 2.5 °C

Question 67

Refer to the map.
The map shows the changes in NPP (per year) between 1982 and 1999. Which place has seen the largest increase in NPP?

A) Central Mexico
B) Spain
C) The Amazon
D) Central Australia

Question 68

During the retreat of continental glaciers in North America during the past 18,000 years, there were some plant communities present that have no present analogs. Which of the following is not a reason that communities did not move due to changes in climate?

A) Individual species differ in dispersal rates.
B) Individual species differ in acclimation and adaptation rates.
C) Biotic interactions, including competition and mutualisms, were altered.
D) Humans caused habitat fragmentation and selective harvest of certain plant species.

Question 69

Which if the following is not a risk factor that will increase the susceptibility of species to extinction due to climate change?

A) Narrow thermal tolerance
B) Low dispersal ability
C) Fragmented habitat
D) Large dispersal barriers

Question 70

The two major compounds in the atmosphere that are responsible for acidic precipitation are _______ and _______.

A) sulfuric acid; nitric acid
B) sulfuric acid; hydrochloric acid
C) ozone; nitric acid
D) ozone; hydrochloric acid

Question 71

As nitrogen input increases, _______ increases at first and then decreases at high levels of nitrogen input.

A) nitrification
B) net primary productivity
C) leaf nitrogen concentration
D) leaching of NO₃^-

Question 72

Refer to the figure.
The figure shows the relationship between the mean number of species per plot and the deposition of inorganic nitrogen in kilograms per hectare per year. Within the scope of this experiment, the deposition of each kilogram per hectare of nitrogen reduced plot species diversity by about _______ species.

A) 0.3
B) 0.7
C) 1.1
D) 2.5

Question 73

Which statement about the stratospheric ozone layer is false?

A) CFCs, used in refrigerants and propellants, react with other chemicals to produce chemicals that destroy ozone molecules.
B) Decreases in protective ozone have been most pronounced near the equator.
C) The levels of the protective ozone layer continued to decline after the Montreal Protocol, due to time lags.
D) Amphibians appear to be particularly susceptible to the increased UV radiation brought about by the decline in the protective ozone layer.

Question 74

Too much ozone in the lower atmosphere is harmful to organisms and ecosystems because it

A) is an oxidant and a greenhouse gas.
B) is a greenhouse gas and causes acid precipitation.
C) it is an oxidant and causes acid precipitation.
D) it is an oxidant, a greenhouse gas, and causes acid precipitation.