When an ecosystem is only rock, no life exists. What form of succession is about to begin?

• pioneer
• primary
• secondary

Resource depletion, pollution, and habitat loss are all environmental problems caused by what factor?

• acid rain
• introduced species
• human activities

Which of the following human activities is most likely to affect water quantity in an area?

• boating on a lake
• constructing a dam
• piloting oil tankers across the ocean

The diagram shows a person commuting to work. Which of the following best describes what the person is doing?

• recycling natural resources
• depleting natural resources
• conserving natural resources

What happens when an ecosystem undergoes eutrophication?

• An exotic species is introduced into a region.
• The density of people living in an area increases.
• The amount of nutrients in an aquatic ecosystem increases.

How might the channelization (used to straighten rivers to improve travel and other activities) of rivers affect populations in river ecosystems?

• Aquatic species might find new food sources.
• Aquatic species might adapt to land environments.
• Aquatic species might lose the conditions they need to survive.

What happens when resource depletion occurs?

• nutrients are added to an aquatic ecosystem
• a large fraction of a specific resource is used up
• materials are changed in form so they can be reused

Farmers often give their crops more nutrients by applying chemical fertilizers to the soil. Which of the following describes how this activity is most likely to affect water quality in nearby water bodies?

• If the fertilizers run off into the water, they can cause eutrophication.
• If the fertilizers run off into the water, the water will be able to support a greater diversity of organisms.
• Applying chemical fertilizers to soil is unlikely to affect water quality in nearby water bodies.

How would the introduction of an exotic species most likely affect an ecosystem?

• It would increase the available resources.
• It would compete with native species for resources.
• It would cause the size of the ecosystem to increase.

How might acid rain harm the environment?

• It traps heat near Earth’s surface.
• It lowers the pH of bodies of water on the ground.
• It allows harmful radiation from the sun to reach Earth.