Question

when plants and animals die, nitrogen is returned to the soil by the process of (nitrogen fixation/ammonification)
your answer

Explanation:

• Nitrogen fixation is the process of converting atmospheric nitrogen (\(N_2\)) into ammonia (\(NH_3\)) or other nitrogen - containing compounds by certain bacteria (e.g., Rhizobium in root nodules of legumes).
• Ammonification is the process by which decomposers (such as bacteria and fungi) break down the organic nitrogen in dead plants and animals (proteins, nucleic acids etc.) into ammonia (\(NH_3\)) which is then released into the soil.

Answer:

ammonification