Nitrogen cycle

What converts nitrogen gas into a usable form for plants and animals?

• bacteria

• rain

• fungi

• car exhaust

The process in which nitrogen circulates and is recycled is called

• The nitrogen cycle

• The carbon cycle

• The water cycle

• The phosphorus cycle

Organisms that need nitrogen to survive.

• only plants

• only animals

• only bacteria

• all living things

How is nitrogen "fixed" into a usable form for plants?

• Through action of bacteria only

• Through lightning only

• Through action of bacteria and lightning

• Through photosynthesis

How do animals get the nitrogen they need?

• From the air they breathe

• From the water they drink

• From the food they eat

• From the sun

What is the process of combining nitrogen gas with other elements to make nitrogen into usable compounds?

• nitrogen composition

• nitrogen fixation

• ammonia

• denitrification

What process occurs when dead plant and animal matter decomposes and nitrogen is released back into the atmosphere?

• Assimilation

• Fixation

• Ammonification

• Denitrification

Plants and animals cannot use nitrogen directly from the air.

• True

• False

Bacteria fix nitrogen from the atmosphere into a form plants can use.

• True

• False

In the nitrogen cycle, what does label A in the diagram represent?

• Gas

• Clouds

• Carbon dioxide in the atmosphere

• Nitrogen in the atmosphere