Nitrogen Cycle Quiz

What is the process by which nitrogen moves around in ecosystems?

• Water cycle

• Oxygen cycle

• Carbon cycle

• Nitrogen cycle

What percentage of our atmosphere is made up of nitrogen gas?

• 50%

• 78%

• 90%

• 65%

What is the name of the bacteria that can break the triple bond of nitrogen gas to make it usable for organisms?

• Denitrifying bacteria

• Nitrifying bacteria

• Nitrogen-fixing bacteria

• Decomposing bacteria

What is the name of the process that converts ammonia into nitrates?

• Nitrogen fixation

• Assimilation

• Denitrification

• Nitrification

What is the name of the process that converts nitrates back into nitrogen gas?

• Nitrogen fixation

• Assimilation

• Nitrification

• Denitrification

Where does nitrification happen best?

• In the atmosphere

• In waterlogged soils

• In well-aerated soils

• In the air

What happens to nitrogen when organisms die and decompose?

• It becomes oxygen

• It becomes ammonia again

• It becomes carbon dioxide

• It becomes water

What is the name of the process that returns the nitrogen back to the soil as ammonia?

• Nitrogen fixation

• Assimilation

• Nitrification

• Ammonification

What is the reason why it's harmful to over water plants?

• It has no effect on the soil

• It increases the fertility of the soil

• It reduces the fertility of the soil

• It makes the soil acidic

What is the name of the molecule needed to make some of the most important molecules for life including DNA, RNA, and proteins?

• Oxygen

• Carbon dioxide

• Hydrogen

• Nitrogen