Which one of the following statements is correct ?

Options

A. Legumes fix nitrogen only through specialized bacteria that live in their roots
B. Legumes fix nitrogen independently of specialized bacteria that live in their roots
C. Legumes fix nitrogen only through specialized bacteria that live in their leaves
D. Legumes are incapable of fixing nitrogen

Answer

To solve the question regarding which statement about legumes and nitrogen fixation is correct, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: We need to identify the correct statement regarding how legumes fix nitrogen.

2. **Analyze Each Statement**:
- **Statement 1**: "Legumes fix nitrogen only through specialized bacteria that live in their roots."
- **Statement 2**: "Legumes fix nitrogen independently of specialized bacteria that live in their roots."
- **Statement 3**: "Legumes fix nitrogen only through specialized bacteria that live in their leaves."
- **Statement 4**: "Legumes are incapable of fixing nitrogen."

3. **Evaluate Statement 1**:
- Legumes form a symbiotic relationship with nitrogen-fixing bacteria called **Rhizobium**, which reside in the roots of the plants. They form root nodules where nitrogen fixation occurs. This statement is correct.

4. **Evaluate Statement 2**:
- This statement claims that legumes can fix nitrogen independently of bacteria. This is incorrect because legumes rely on Rhizobium for nitrogen fixation.

5. **Evaluate Statement 3**:
- This statement suggests that nitrogen fixation occurs in the leaves. This is incorrect as the nitrogen-fixing bacteria are located in the roots, not the leaves.

6. **Evaluate Statement 4**:
- This statement claims that legumes cannot fix nitrogen. This is false since legumes are well-known for their ability to fix nitrogen through their symbiotic relationship with Rhizobium.

7. **Conclusion**:
- The only correct statement is **Statement 1**: "Legumes fix nitrogen only through specialized bacteria that live in their roots."

### Final Answer:
The correct statement is: **Legumes fix nitrogen only through specialized bacteria that live in their roots.**

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