Nitrogenase in an enzyme used in :

Options

A. Respiration
B. Nitrogen oxidation
C. Nitrogen reduction
D. Both (B) and (C )

Answer

**Step-by-Step Solution:**

1. **Understanding Nitrogenase**: Nitrogenase is an enzyme that plays a crucial role in the nitrogen cycle. It is primarily involved in the process of nitrogen fixation, which is the conversion of atmospheric nitrogen (N₂) into ammonia (NH₃).

2. **Analyzing the Options**:
- **Option A: Respiration**: This option is incorrect because respiration refers to the metabolic process of converting glucose and oxygen into energy, carbon dioxide, and water. It does not involve nitrogenase.
- **Option B: Nitrogen Oxidation**: This option is also incorrect. Nitrogen oxidation occurs during nitrification, where ammonia is converted to nitrite and then to nitrate. This process does not involve nitrogenase.
- **Option C: Nitrogen Reduction**: This option is correct. Nitrogenase catalyzes the reduction of dinitrogen (N₂) to ammonia (NH₃), which is a key step in nitrogen fixation.

3. **Conclusion**: Based on the analysis, the correct answer is **Option C: Nitrogen Reduction**. Nitrogenase is specifically involved in the reduction of nitrogen gas to ammonia.