Assertion: Pyrenoids may or may not be surrounded by a sheath of starch plates in algae.
Reason: In higher plants, these are replaced by amyloplasts.

Options

A. If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
B. If both Assertion and Reason are true, but the Reason is not the correct explanation of the Assertion.
C. If Assertion is true, but Reason is false.
D. If both Assertion and Reason are false.

Answer

To solve the question, we need to analyze both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Pyrenoids may or may not be surrounded by a sheath of starch plates in algae."
- Pyrenoids are structures found in certain algae that are involved in the synthesis and storage of starch. It is true that in some algae, pyrenoids can be surrounded by a sheath of starch plates, while in others, they may not be.

2. **Understanding the Reason**:
- The reason given is "In higher plants, these are replaced by amyloplasts."
- Amyloplasts are specialized organelles in higher plants that store starch. They are indeed responsible for starch storage, similar to the function of pyrenoids in algae.

3. **Evaluating the Truth of Both Statements**:
- Both the assertion and the reason are true statements. However, we need to determine if the reason correctly explains the assertion.
- The assertion discusses the presence of pyrenoids in algae, while the reason discusses amyloplasts in higher plants. Although both statements are true, the reason does not directly explain the assertion about pyrenoids in algae.

4. **Conclusion**:
- Since both the assertion and the reason are true, but the reason does not provide a correct explanation for the assertion, the correct answer is that both the assertion and reason are true, but the reason is not the correct explanation of the assertion.

### Final Answer:
The correct option is: Both assertion and reason are true, but the reason is not the correct explanation of the assertion.

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