Assertion : The parasitic fungi cause a number of diseases in plants.
Reason : Fungi are involved in nutrient cycling.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Assertion:**
- The assertion states that parasitic fungi cause a number of diseases in plants. This is true as many fungi are known to be pathogens that infect plants, leading to various diseases such as rots and spots.

2. **Understanding the Reason:**
- The reason provided is that fungi are involved in nutrient cycling. This is also true, as fungi play a crucial role in decomposing organic matter, which helps in recycling nutrients back into the ecosystem.

3. **Analyzing the Relationship:**
- While both the assertion and the reason are correct, we need to analyze whether the reason explains the assertion. The assertion talks specifically about the harmful effects of parasitic fungi on plants, while the reason discusses the beneficial role of fungi in nutrient cycling.

4. **Conclusion:**
- Since the reason does not explain why parasitic fungi cause diseases in plants, we conclude that both statements are correct, but the reason is not the correct explanation for the assertion.

5. **Final Answer:**
- The correct option is that both the assertion and reason are correct, but the reason is not the correct explanation for the assertion.

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