Which of the following best describes the primary function of photosynthesis in the context of the nitrogen cycle?

• A. Photosynthesis provides the organic compounds and energy required by plants, which indirectly supports nitrogen fixation by soil bacteria.
• B. Photosynthesis is responsible for the nitrification process, converting ammonia into nitrate.
• C. Photosynthesis converts atmospheric nitrogen (\(N_2\)) directly into ammonia (\(NH_3\)) for plant use.
• D. Photosynthesis releases nitrogen gas back into the atmosphere during the light-dependent reactions.

Answer: (A)

Verified step by step guidance

1. Understand the primary function of photosynthesis: Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy stored in glucose. It primarily involves the fixation of carbon dioxide (\(CO_2\)) into organic compounds, not nitrogen (\(N_2\)).
2. Clarify the role of photosynthesis in the nitrogen cycle: Photosynthesis provides the energy (in the form of glucose) and organic compounds that plants and other organisms use. This energy indirectly supports nitrogen-fixing bacteria in the soil, which convert atmospheric nitrogen (\(N_2\)) into ammonia (\(NH_3\)) that plants can use.
3. Eliminate incorrect options: Photosynthesis does not directly participate in the nitrification process (conversion of ammonia into nitrate) or the conversion of atmospheric nitrogen (\(N_2\)) into ammonia (\(NH_3\)). These processes are carried out by specific soil bacteria, not by photosynthesis.
4. Address the light-dependent reactions: The light-dependent reactions of photosynthesis involve the production of ATP and NADPH, as well as the release of oxygen (\(O_2\)) from water. Nitrogen gas (\(N_2\)) is not released during these reactions.
5. Conclude the correct answer: The best description of the primary function of photosynthesis in the context of the nitrogen cycle is that it provides the organic compounds and energy required by plants, which indirectly supports nitrogen fixation by soil bacteria.