Bacterium present in root nodules of pea is

Options

A. Lactobacillus
B. E. coli
C. Rhizobium
D. Plasmodium.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the specific bacterium that is found in the root nodules of pea plants.

2. **Identifying the Options**: The options provided are:
- a) Lactobacillus
- b) E. coli
- c) Rhizobium
- d) Plasmodium

3. **Analyzing Each Option**:
- **Lactobacillus**: This bacterium is known for its role in fermentation and is commonly found in the gut, but it is not associated with root nodules of legumes.
- **E. coli**: This bacterium is primarily found in the intestines of humans and animals and is not related to root nodules.
- **Rhizobium**: This is a symbiotic bacterium that specifically forms nodules on the roots of leguminous plants, including peas. It is known for its ability to fix atmospheric nitrogen, making it essential for plant nutrition.
- **Plasmodium**: This is a protozoan parasite that causes malaria in humans and is not related to plants or root nodules.

4. **Conclusion**: Based on the analysis, the correct answer is **c) Rhizobium**, as it is the bacterium that resides in the root nodules of pea plants and plays a crucial role in nitrogen fixation.

**Final Answer**: The bacterium present in root nodules of pea is **Rhizobium**.

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