The root nodules of plants, such as pea, contain Rhizobium bacteria that replenish nitrogen in the soil.

Options

A. Leguminous
B. Gametophytes
C. Non-leguminous
D. Both (b) and ( c)

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the type of plants that have root nodules containing Rhizobium bacteria, which help in replenishing nitrogen in the soil.

2. **Identifying the Key Term**: The key term in the question is "leguminous plants." These are plants that have a symbiotic relationship with nitrogen-fixing bacteria.

3. **Role of Rhizobium Bacteria**: Rhizobium bacteria live in the root nodules of leguminous plants (like peas and gram). They have the ability to convert atmospheric nitrogen into a form that plants can use.

4. **Definition of Leguminous Plants**: Leguminous plants are defined as those that have root nodules containing Rhizobium bacteria. This characteristic allows them to fix nitrogen from the atmosphere.

5. **Examples of Leguminous Plants**: Common examples include the pea plant and gram plant. These plants are known for their ability to enrich the soil with nitrogen.

6. **Conclusion**: Therefore, the answer to the question is that the plants which fix nitrogen in their roots are called "leguminous plants."

### Final Answer:
The plants that fix nitrogen in their roots are called **leguminous plants**.

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