Major nitrogen flxation is carried out by

Options

A. lightning
B. chemical industries
C. symbiotic bacteria
D. leaching

Answer

**Step-by-Step Solution:**

1. **Understanding Nitrogen Fixation**: Nitrogen fixation is the process of converting atmospheric nitrogen (N₂) into ammonia (NH₃). This is essential for plants since they cannot utilize atmospheric nitrogen directly.

2. **Identifying the Mechanisms of Nitrogen Fixation**: There are several mechanisms through which nitrogen fixation occurs:
- **Lightning**: This natural phenomenon can convert atmospheric nitrogen into nitrates.
- **Chemical Industries**: Industrial processes can also fix nitrogen, primarily for fertilizers.
- **Symbiotic Bacteria**: Certain bacteria can fix nitrogen in a symbiotic relationship with plants.
- **Leaching**: This refers to the process of nutrients being washed away from the soil, which does not contribute to nitrogen fixation.

3. **Focusing on Symbiotic Bacteria**: Among the options, symbiotic bacteria are known for their significant role in nitrogen fixation. These bacteria, such as Rhizobium, form a symbiotic relationship with leguminous plants. They attach to the roots of these plants and form root nodules.

4. **Role of Nitrogenase**: The enzyme nitrogenase is crucial for the conversion of atmospheric nitrogen into ammonia. This enzyme is produced by the symbiotic bacteria, enabling them to fix nitrogen effectively.

5. **Conclusion**: Given the options provided and the mechanisms of nitrogen fixation discussed, the major nitrogen fixation is primarily carried out by symbiotic bacteria.

**Final Answer**: The correct answer is **Option C: Symbiotic Bacteria**.

---