The Nitrogen Cycle

Multiple Choice

What % of the air is made of nitrogen?

• 21%

• 52%

• 61%

• 78%

Multiple Choice

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

• bacteria

• rain

• fungi

• car exhaust

Multiple Choice

The process in which nitrogen circulates and is recycled is called

• The nitrogen cycle

• The carbon cycle

• The water cycle

• The phosphorus cycle

Multiple Choice

True or False. The nitrogen in the atmosphere is in the right form for living things to use.

• True

• False

Multiple Choice

Organisms that need nitrogen to survive.

• only plants

• only animals

• only bacteria

• all living things

Multiple Choice

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

Multiple Choice

This can transform nitrogen in the atmosphere into a usable form of nitrogen

• rain

• ice

• lightning

• sun

Multiple Choice

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

Multiple Choice

Gas that makes up 78% of our atmosphere.

• Oxygen

• Nitrogen

• Hydrogen

• Carbon Dioxide

Multiple Choice

What is the role of denitrifying bacteria

• change nitrate back into nitrogen gas

• change nitrogen gas into nitrate

• absorb carbon dioxide in the soil

• release oxygen gas into the atmosphere

Multiple Choice

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

• nitrogen composition

• nitrogen fixation

• ammonia

• denitrification

Multiple Choice

Round structures on the roots of certain plants

• lichens

• commensals

• cataracts

• nodules

Multiple Choice

What is the formula for atmospheric nitrogen?

• N

• N₂

• NH₃

• NO₃

Multiple Choice

What is the role of decomposing bacteria in the nitrogen cycle?

• change Nitrogen gas into Nitrate

• Return the nitrogen compounds to the soil

• Turn nitrogen into water

• Turn nitrate into nitrogen gas

Multiple Choice

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

• Assimilation

• Fixation

• Ammonification

• Denitrification

Multiple Choice

We need nitrogen to make

• proteins

• enzymes

• cells

• all of these

Multiple Choice

Plants and animals cannot use nitrogen directly from the air.

• True

• False

Multiple Choice

Burning fossil fuels releases this into the air

• nitrous oxide

• nitrate

• nitrogen gas (N2)

• methane

Multiple Choice

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

• True

• False

Multiple Select

How does fertilizer affect the nitrogen cycle

• 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

Multiple Choice

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

• Gas

• Clouds

• Carbon dioxide in the atmosphere

• Nitrogen in the atmosphere

Multiple Select

Where can nitrogen fixing bacteria be found

• Free living in the soil

• under the leaves of flowering plants

• in the atmosphere

• living on the nodules of certain plants

Multiple Choice

Plants and animals need nitrogen to make __________.

• Protein
• Carbohydrates
• Lipids
• Minerals

Multiple Select

What plants help or are beneficial to the nitrogen cycle?

• pear trees

• peas

• dandelions

• clover

• peanuts

Multiple Choice

What does the color green indicate on the map

• 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