Nitrogen cycle

How much of the atmosphere is composed of nitrogen gas?

• 88%

• 78%

• 100%

• 87%

Plants and animals cannot use nitrogen directly from the air.

• true

• false

Atmospheric Nitrogen is easily taken up and used by organisms.

• true

• false

Nitrification happens in the .....

• water

• air

• soil

• bacteria

Organisms that need nitrogen to survive

• all living organisms

• only plants

• only animals

• only bacteria