Leghaemoglobin functions as

Options

A. oxygen scavenger
B. nitrogen scavenger
C. `CO_(2)` scavenger
D. hydrogen carrier

Answer

### Step-by-Step Solution:

1. **Understanding Leghemoglobin**: Leghemoglobin is a protein found in the root nodules of leguminous plants. It is similar to hemoglobin in animals and plays a crucial role in the process of nitrogen fixation.

2. **Role in Nitrogen Fixation**: Nitrogen fixation is the process where atmospheric nitrogen (N2) is converted into ammonia (NH3), which plants can use. This process is primarily carried out by certain prokaryotes (bacteria) that have the enzyme nitrogenase.

3. **Sensitivity of Nitrogenase**: The enzyme nitrogenase, which is responsible for the conversion of nitrogen to ammonia, is highly sensitive to oxygen. While nitrogen fixation requires a low-oxygen environment, the presence of oxygen can inhibit the activity of nitrogenase.

4. **Function of Leghemoglobin**: Leghemoglobin functions as an oxygen scavenger. It binds to free oxygen in the root nodules, thus maintaining a low-oxygen environment that is conducive for the nitrogenase enzyme to function effectively.

5. **Conclusion**: Therefore, the primary function of leghemoglobin is to act as an oxygen scavenger, protecting the nitrogen-fixing bacteria and their nitrogenase enzyme from oxygen, thereby facilitating the process of nitrogen fixation.

### Final Answer:
Leghemoglobin functions as an oxygen scavenger.

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