Nitrogen Cycle

Question 1

Nitrogen essential component of

Answer 1

Proteins

Question 2

Nitrogen is most abundant gas in

Answer 2

Atmosphere

Question 3

Because nitrogen is unreactive, most living things rely on _ to fix nitrogen from air

Answer 3

Bacteria

Question 4

Bacteria fix, or assimilate, nitrogen from air, converting it into _ for other organisms to use

Answer 4

Nitrates

Question 5

3.5 billion people depend on _ to grow food

Answer 5

Synthetic nitrate fertilizer

Question 6

Some plants have _ in their roots

Answer 6

Nitrogen-fixing bacteria

Question 7

Animals die and bacteria and fungi (decomposers) release simple nitrogen compounds such as

Answer 7

Ammonia

Question 8

Bacteria in soil convert ammonia into

Answer 8

Organic nitrate compounds

Question 9

_ combines nitrogen and oxygen in air

Answer 9

Lightening

Question 10

_ fix nitrogen gas from air

Answer 10

Nitrifting bacteria

Question 11

Past 2 centuries, fossil fuel burning has transferred _ from underground carbon sinks

Answer 11

Several billion tons of carbon

Question 12

Added carbon

Answer 12

Traps heat

Question 13

Heat changes global climate and

Answer 13

Creates extreme weather