Assertion: Removal of key stone species from any ecosystem leads to destruction of entrie ecosystem.
Reason: Keystone species drive major ecosystem functions.

Options

A. If both Assertion `&` Reason are True `&` the Reason is a correct explanation of the Assertion.
B. If both Assertion `&` Reason are True but Reason is not a correct explanation of the Assertion
C. If Assertion is True but the Reason if False.
D. If both Assertion `&` Reason are false.

Answer

### Step-by-Step Solution:

1. **Understanding the Assertion**: The assertion states that the removal of keystone species from an ecosystem leads to the destruction of the entire ecosystem. This means that keystone species are critical for maintaining the structure and function of their ecosystems.

2. **Defining Keystone Species**: Keystone species are those species that have a disproportionately large effect on their environment relative to their abundance. They play crucial roles in the ecosystem, such as predators, prey, or even as ecosystem engineers.

3. **Analyzing the Reason**: The reason provided states that keystone species drive major ecosystem functions. This implies that these species are essential for various ecological processes, such as nutrient cycling, population control, and habitat maintenance.

4. **Connecting Assertion and Reason**: The assertion and reason are closely related. If keystone species are removed, the functions they perform are disrupted, which can lead to a cascade of negative effects on the ecosystem, ultimately leading to its destruction.

5. **Conclusion**: Since both the assertion and the reason are true, and the reason correctly explains the assertion, we conclude that the correct answer is that both the assertion and reason are true, and the reason is the correct explanation for the assertion.

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

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