- A Converting atmospheric N2 gas directly into ammonia by nitrogenase
- B Converting dead organic matter (proteins) back to ammonia by decomposers
- C Oxidizing ammonia stepwise into nitrite and then nitrate
- D Direct uptake of ammonia ions through plant root hairs
Correct answer: B. Converting dead organic matter (proteins) back to ammonia by decomposers
Explanation: Ammonification is the decomposition of organic nitrogen (from dead organisms and waste) back to NH3/NH4+ by putrefying bacteria and fungi. It is part of the nitrogen cycle that returns organic nitrogen to the soil.
Concept context
Essential mineral elements, their roles and deficiency symptoms. Nitrogen fixation and soil nutrition.