The Nitrogen Cycle

21%

52%

61%

78%

bacteria

rain

fungi

car exhaust

The nitrogen cycle

The carbon cycle

The water cycle

The phosphorus cycle

True

False

only plants

only animals

only bacteria

all living things

Through action of bacteria only

Through lightning only

Through action of bacteria and lightning

Through photosynthesis

rain

ice

lightning

sun

From the air they breathe

From the water they drink

From the food they eat

From the sun

Oxygen

Nitrogen

Hydrogen

Carbon Dioxide

change nitrate back into nitrogen gas

change nitrogen gas into nitrate

absorb carbon dioxide in the soil

release oxygen gas into the atmosphere

nitrogen composition

nitrogen fixation

ammonia

denitrification

lichens

commensals

cataracts

nodules

N

N₂

NH₃

NO₃

change Nitrogen gas into Nitrate

Return the nitrogen compounds to the soil

Turn nitrogen into water

Turn nitrate into nitrogen gas

Assimilation

Fixation

Ammonification

Denitrification

proteins

enzymes

cells

all of these

True

False

nitrous oxide

nitrate

nitrogen gas (N2)

methane

True

False

the bacteria reproduce quicker

cause nitrous oxide, a greenhouse gas, to enter the atmosphere and trap heat

create large algae blooms in the water

cause the nitrogen fixing bacteria in the soil to be less productive

Gas

Clouds

Carbon dioxide in the atmosphere

Nitrogen in the atmosphere

Free living in the soil

under the leaves of flowering plants

in the atmosphere

living on the nodules of certain plants

pear trees

peas

dandelions

clover

peanuts

There was a deficiency of nitrogen fertilizer in the soil

There was an excess of nitrogen fertilizer in the soil

There was exactly enough nitrogen fertilizer in the soil

No fertilizer was used