Name the micro - organisms present in the soil and in the root nodules of leguminous plants which can fix atmospheric nitrogen.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the microorganisms that are present in the soil and in the root nodules of leguminous plants that can fix atmospheric nitrogen.

2. **Identifying Leguminous Plants**: Leguminous plants are a group of plants that include peas, beans, lentils, and clover. These plants have a special relationship with certain bacteria that help them obtain nitrogen.

3. **Role of Microorganisms**: The microorganisms that are specifically associated with the root nodules of leguminous plants are responsible for fixing atmospheric nitrogen. This means they convert nitrogen gas from the atmosphere into a form that plants can use.

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