Which one of the following is useful in Rice fields

Options

A. Rhizobium
B. Clostridium
C. Anabaena
D. Ferrobacterium

Answer

**Step-by-Step Solution:**

1. **Understanding the Question:**
The question asks which of the given bacteria is useful in rice fields. We need to analyze each option to determine which one is beneficial for rice cultivation.

2. **Analyzing the Options:**
- **Rhizobium:** This bacterium forms a symbiotic relationship with leguminous plants (like peas and lentils) and is primarily known for nitrogen fixation in those plants. It does not have a direct role in rice fields.
- **Clostridium:** This bacterium is free-living and can fix nitrogen, but it does not form a symbiotic relationship with plants. While it can help in nitrogen fixation, it is not specifically beneficial for rice fields.
- **Anabaena:** This is a type of blue-green algae that can live in symbiotic relationships with certain plants, including rice. Anabaena is known for its ability to fix nitrogen, which is beneficial for rice cultivation.
- **Ferrobacterium:** This bacterium uses iron as a source of energy and is not associated with nitrogen fixation or beneficial for rice fields.

3. **Identifying the Correct Answer:**
Based on the analysis, Anabaena is the bacterium that is specifically useful in rice fields due to its nitrogen-fixing ability and symbiotic relationship with rice plants.

4. **Conclusion:**
The correct answer is **C. Anabaena**.

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