A red pigment leghaemoglobin in root nodules a legumes is helpful in nitrogen fixation by :

Options

A. Providing oxygen
B. Helping all aerobic respiration
C. Removal of oxygen
D. None of the above

Answer

### Step-by-Step Solution:

1. **Understanding the Role of Leghemoglobin**:
- Leghemoglobin is a red pigment found in the root nodules of legumes. It plays a crucial role in the process of nitrogen fixation.

2. **Identifying the Function of Leghemoglobin**:
- The primary function of leghemoglobin is to provide a controlled supply of oxygen (O2) to the nitrogen-fixing bacteria (Rhizobium) present in the root nodules.

3. **Importance of Oxygen in Nitrogen Fixation**:
- Nitrogen fixation is the process where atmospheric nitrogen (N2) is converted into ammonia (NH3) by the enzyme nitrogenase.
- Nitrogenase is sensitive to oxygen; therefore, it requires a low concentration of oxygen to function effectively.

4. **How Leghemoglobin Helps**:
- Leghemoglobin binds to oxygen and regulates its availability, ensuring that there is enough oxygen for aerobic respiration of the bacteria while simultaneously protecting nitrogenase from inactivation due to excess oxygen.

5. **Conclusion**:
- The correct answer to the question is that leghemoglobin helps in nitrogen fixation by **providing oxygen** to the nitrogen-fixing bacteria, which is essential for the activity of nitrogenase.

### Final Answer:
Leghemoglobin in root nodules of legumes is helpful in nitrogen fixation by **providing oxygen**.

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