Assertion : Endomycorrhiza of forest trees contribute to the efficient nutrient cycling in tropical forest ecosystem.
Reason : The fungi that form mycorrhizal associations with plants make nutrient ions available to them.

Options

A. Point out if both are true with reason being correct explanation
B. both true but reason is nut correct explanation
C. assertion true but reason is wrong
D. both are wrong

Answer

To analyze the assertion and reason provided in the question, we can break down the solution into a series of steps:

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that endomycorrhiza of forest trees contribute to efficient nutrient cycling in tropical forest ecosystems.
- **Explanation**: Endomycorrhizae are a type of mycorrhizal association where fungi penetrate the root cells of plants. This symbiotic relationship enhances nutrient uptake, particularly phosphorus, which is crucial for plant growth.

2. **Understanding the Reason**:
- The reason states that fungi that form mycorrhizal associations with plants make nutrient ions available to them.
- **Explanation**: Mycorrhizal fungi increase the surface area for absorption and help in breaking down organic matter, thus making essential nutrients more accessible to the plants.

3. **Evaluating the Truth of the Statements**:
- Both the assertion and the reason are true statements.
- The assertion is true because endomycorrhizae do indeed facilitate nutrient cycling in ecosystems, particularly in nutrient-poor tropical forests.
- The reason is also true as it correctly describes the role of mycorrhizal fungi in nutrient availability.

4. **Relationship Between Assertion and Reason**:
- The reason provides a correct explanation for the assertion. It explains how endomycorrhizae contribute to nutrient cycling by making nutrients available to plants.
- Therefore, the reason supports the assertion.

5. **Conclusion**:
- Since both statements are true and the reason correctly explains the assertion, the answer to the question is that both the assertion and reason are true, with the reason being a correct explanation of the assertion.

### Final Answer:
Both the assertion and reason are true, and the reason is a correct explanation of the assertion.

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