Nitrogen Cycle

How nitrogen is "fixed" into useable form for plants

• only through action of bacteria
• only through lightning
• through action of bacteria & lightning
• through photosynthesis

Why do all organisms need nitrogen?

• To live and grow 
• To build phosphorus
• To make oxygen levels grow
• To help blood circulate better

Nitrogen fixing bacteria, lives in nodules on the root of a plant called

• Broccoli
• Legumes
• Beats
• Carrots

Where does nitrogen go once it is in the soil?

• stems of plants

• leaves of plants

• roots of plants

• flowers of plants

Animals get nitrogen by ____________.

• breathing air

• eating plants

• dying

• being struck by lightning

Algal blooms usually occur when nitrogen increases in the

• air.

• water.

• soil.

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

• nitrogen composition
• ammonia 
• nitrogen fixation
• denitrification

How much of the atmosphere is composed of nitrogen gas?

• 87%
• 38%
• 78%
• 21%

_____ is the conversion of organic nitrogen into ammonia

• Nitrogen Fixation
• Ammonification
• Denitrification
• Assimilation 

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

• bacteria

• rain

• fungi

• car exhaust