Assertion: Secondary succession always involves a predictable sequence of species and ends up with the same climax community as existed prior to the disturbance.
Reason: A pond cannot be considered as a self sustained ecosystem as it does not possess all the structural and functional components which work as a unit in an ecosystem.

Options

A. a) Both assertion and reason are correct and reason is the correct explanation for assertion.
B. b) Both assertion and reason are correct but reason is not the correct explanation for assertion.
C. c) Assertion is correct and reason is incorrect.
D. d) Both assertion and reason are incorrect.

Explanation

To analyze the assertion and reason provided in the question, we will break down each statement step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Secondary succession always involves a predictable sequence of species and ends up with the same climax community as existed prior to the disturbance."
- **Evaluation**: Secondary succession does not always follow a predictable sequence. Various factors, such as chance events or the introduction of new species, can alter the expected sequence. Additionally, the climax community that develops may differ from the original due to changes in environmental conditions.

2. **Understanding the Reason**:
- The reason states that "A pond cannot be considered a self-sustained ecosystem as it does not possess all the structural and functional components which work as a unit in an ecosystem."
- **Evaluation**: This statement is incorrect. A pond is indeed considered a self-sustained ecosystem. It contains both biotic (living organisms) and abiotic (non-living components) factors that interact and function together as an ecosystem.

3. **Conclusion**:
- Since both the assertion and the reason are incorrect, we conclude that the correct answer is that both the assertion and the reason are false.

### Final Answer:
Both the assertion and the reason are incorrect.

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