Explain how Rhizobium bacteria help in nitrogen fixation.

Explanation

**Step-by-Step Solution:**

1. **Understanding Nitrogen Fixation:**
- Nitrogen fixation is the process through which atmospheric nitrogen (N₂) is converted into a form that plants can use, primarily ammonia (NH₃). Plants cannot directly utilize atmospheric nitrogen.

2. **Role of Rhizobium:**
- Rhizobium is a type of bacteria that plays a crucial role in nitrogen fixation. It is a prokaryotic organism that is specifically known for its ability to fix nitrogen.

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