Frankia is a member of actinomycetes which increase the `N_(2)` content of the soil and can infect the roots of :

Options

A. Gram
B. Pea
C. Casuarina
D. Wheat

Answer

**Step-by-Step Solution:**

1. **Understanding Frankia**: Frankia is a genus of actinomycetes known for its ability to fix nitrogen. This means it can convert atmospheric nitrogen (N₂) into a form that plants can use, which is essential for their growth.

2. **Identifying the Symbiotic Relationship**: Frankia forms a symbiotic relationship with certain plants. In this relationship, the bacteria provide nitrogen to the plant, while the plant supplies carbohydrates and a suitable environment for the bacteria.

3. **Analyzing the Options**: The question provides four options: A. gram, B. pea, C. cassiopeia, D. wheat. We need to identify which of these plants can form a symbiotic relationship with Frankia.

4. **Recognizing the Correct Plant**: Among the options, Cassiopeia (specifically Cassiopeia arena) is known to be associated with Frankia. This plant forms root nodules where Frankia resides and fixes nitrogen.

5. **Conclusion**: Therefore, the correct answer to the question is C. cassiopeia.

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