choose the correct option w.r.t. leg- haemoglobin

Options

A. Found in root nodules of grasses
B. Oxygen scavenger
C. Provides suitable conditions for nitrogenase activity
D. Both (2) and (3)

Answer

To solve the question regarding leg-haemoglobin, let's analyze the options step by step.

### Step 1: Understand what leg-haemoglobin is
Leg-haemoglobin is a protein found in the root nodules of leguminous plants. Its primary role is to facilitate the supply of oxygen to nitrogen-fixing bacteria, such as Rhizobium, which reside in these nodules.

**Hint:** Remember that leg-haemoglobin is specific to leguminous plants, not grasses.

### Step 2: Analyze the options
1. **Found in root nodules of grasses**: This statement is incorrect. Leg-haemoglobin is specifically found in the root nodules of legumes, not grasses.

2. **Oxygen scavenger**: This statement is correct. Leg-haemoglobin acts as an oxygen scavenger by binding to oxygen, which helps to create an anaerobic environment necessary for the nitrogenase enzyme to function effectively.

3. **Provides suitable conditions for nitrogenase activity**: This statement is also correct. By binding to oxygen, leg-haemoglobin protects the nitrogenase enzyme from inactivation by oxygen, thus providing the necessary conditions for nitrogen fixation.

### Step 3: Conclusion
Based on the analysis:
- The first option is incorrect.
- The second and third options are correct.

Therefore, the correct answer to the question is **both 2 and 3**.

### Final Answer:
The correct option with respect to leg-haemoglobin is **both 2 and 3**.