Question

the following diagram describes the nitrogen cycle. arrow i shows nitrogen moving from microorganisms in the soil to the atmosphere. which process is represented by arrow i? choose 1 answer: a nitrification b nitrogen fixation c denitrification d ammonification

Explanation:

To determine the process of Arrow I, we analyze each option:

• Nitrification: Involves converting ammonia to nitrates, not releasing N₂ to atmosphere. Eliminate A.
• Nitrogen fixation: Converts atmospheric N₂ to usable forms (e.g., NH₃), opposite of Arrow I. Eliminate B.
• Denitrification: Denitrifying microorganisms convert soil nitrates (or related forms) to N₂ gas, releasing it to the atmosphere. This matches Arrow I (microorganisms in soil → atmosphere with N₂).
• Ammonification: Decomposers convert organic nitrogen to ammonia, no N₂ release. Eliminate D.

Answer:

C. denitrification