The enzyme responsible for the reduction of molecular nitrogen to the level of amonia in leguminous root nodule is
Or
The enzyme reponsible for atmospheric nitrogen fixation is

Options

A. Nitrogenase
B. Nitroreductase
C. Transferase
D. Transaminase

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the enzyme that reduces molecular nitrogen (N₂) to ammonia (NH₃) in leguminous root nodules, which is also responsible for atmospheric nitrogen fixation.

2. **Identifying the Enzymes**: The options provided are:
- Option 1: Nitrogenase
- Option 2: Nitro reductase
- Option 3: Transferase
- Option 4: Transaminase

3. **Analyzing the Options**:
- **Nitrogenase**: This enzyme is specifically known for its role in nitrogen fixation, converting molecular nitrogen (N₂) into ammonia (NH₃) in the root nodules of leguminous plants.
- **Nitro Reductase**: This enzyme is involved in the reduction of nitro compounds, not directly in nitrogen fixation.
- **Transferase**: This group of enzymes is involved in transferring functional groups, not specifically in nitrogen fixation.
- **Transaminase**: This enzyme is involved in amino acid metabolism and does not play a direct role in nitrogen fixation.

4. **Conclusion**: Since nitrogenase is the enzyme responsible for the reduction of molecular nitrogen to ammonia in leguminous root nodules, the correct answer is **Nitrogenase**.

### Final Answer:
The enzyme responsible for the reduction of molecular nitrogen to the level of ammonia in leguminous root nodules is **Nitrogenase**.

---