Front

emissions

Back

Pollutants that are released into the air.

Front

overpopulation

Back

a condition in which the number of humans grows beyond what the available resources can support

Front

fossil fuel

Back

Energy-rich substance formed from the remains of organisms.

Front

erosion

Back

The process by which water, ice, wind, or gravity moves weathered particles of rock and soil.

Front

deposition

Back

Process in which sediment is laid down in new locations.

Front

petroleum

Back

liquid fossil fuel

Front

deforestation

Back

the removal of forests to use the land for other reasons

Front

renewable resource

Back

A resource that is either always available or is naturally replaced in a relatively short time.

Front

nonrenewable resource

Back

A natural resource that is not replaced in a useful time frame.

Front

exponential growth

Back

A rate of change that increases more and more rapidly over time.