Ecosystems and Biomes

The air is mostly nitrogen gas.

A forest fire started by lightning is an example of a natural disaster.

Some bacteria found in soil can turn nitrogen gas into potassium, which is used by plants.

Animals can obtain carbon-rich chemicals by eating plants or eating animals that eat plants.

The boundary where a river feeds into the ocean is called a pond.

Groundwater is stored in tiny holes in soil and rocks.

Ecosystems cannot be changed by humans.

Reptiles found in a hot desert are active only at night.

A tropical rain forest is rich with life, but it has nutrient-poor soil.

Sunlight reaches the abyssal zone of the ocean where many types of organisms can be found.