Rhizobium bacteria ________.

Options

A. help in digestion
B. help in nitrogen fixation
C. cause diseases
D. all of the above

Answer

**Step-by-Step Solution:**

1. **Understanding Rhizobium Bacteria**: Rhizobium is a type of bacteria that forms a symbiotic relationship with leguminous plants. This means it lives in close association with the roots of these plants.

2. **Role in Nitrogen Fixation**: The primary function of Rhizobium bacteria is nitrogen fixation. They have the ability to convert atmospheric nitrogen (N₂) into a form that plants can use (like ammonia). This process is crucial because most plants cannot utilize atmospheric nitrogen directly.

3. **Location of Rhizobium**: Rhizobium bacteria reside in root nodules of leguminous plants. These nodules are specialized structures that provide a suitable environment for the bacteria to thrive and perform nitrogen fixation.

4. **Conclusion**: Given the options provided in the question (helps in digestion, helps in nitrogen fixation, causes diseases, or all of the above), the most accurate statement about Rhizobium bacteria is that they help in nitrogen fixation.

**Final Answer**: Rhizobium bacteria help in nitrogen fixation.

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