U1L7 Nitrogen WG APES

Multiple Choice

Which gas makes up the largest percentage of Earth's atmosphere?

• Oxygen

• Carbon dioxide

• Nitrogen

• Hydrogen

Multiple Select

Which of the following are phases of the nitrogen cycle? SELECT ALL THAT APPLY

• Fixation

• Photosynthesis

• Nitrification

• Denitrification

Multiple Choice

What must happen to nitrogen gas (N2) for it to become biologically available to plants?

• It must be dissolved in water

• It must be fixed or combined with hydrogen to form ammonia

• It must be exposed to sunlight

• It must be converted to oxygen

Multiple Choice

What is the role of lightning in the nitrogen cycle as depicted in the images?

• It breaks the triple bond in nitrogen molecules, making nitrogen available for other processes.

• It directly provides nitrogen to plants.

• It kills nitrogen-fixing bacteria.

• It converts ammonia to nitrate.

Multiple Choice

During assimilation, how do plants primarily absorb nitrogen from the soil?

• Through their root hairs as nitrate or ammonium ions

• Through their leaves as nitrogen gas

• By absorbing proteins from decaying animals

• By photosynthesis

Multiple Choice

Which of the following statements about denitrification are correct?

• Denitrification converts nitrates into nitrogen gas, returning it to the atmosphere.

• Denitrification is the same as ammonification.

• Denitrification adds nitrogen to the soil.

• Denitrification is performed by plants.