Assertion: The respiratory activity in cell maturation phase as compared to other phases is less.
\ Reason: If total growth is plotted against time, the curve obtained is known as S-shaped curve.

Options

A. If both Assertion and Reason are true and the Reason is a correct explanation of the Assertion.
B. If both Assertion and Reason are true but the Reason is not a correct explanation of the Assertion.
C. If Assertion is true but the 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, and determine their truthfulness and relationship.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "The respiratory activity in the cell maturation phase as compared to other phases is less."
- In the cell maturation phase, cells have reached their maximum size and are primarily involved in maintaining their structure rather than actively growing. As a result, their metabolic activity, including respiration, decreases compared to earlier growth phases.

2. **Understanding the Reason**:
- The reason states that "If total growth is plotted against time, the curve obtained is known as S-shaped curve."
- This is a well-known concept in biology. When growth is plotted over time, it typically follows an S-shaped curve, which includes phases such as lag, exponential (log), and stationary phases.

3. **Evaluating the Truth of Each Statement**:
- Both the assertion and the reason are true. The assertion correctly describes the reduced respiratory activity during the maturation phase, and the reason accurately describes the S-shaped growth curve.

4. **Determining the Relationship**:
- The reason does not provide a correct explanation for the assertion. While both statements are true, the reason does not explain why respiratory activity is less during the maturation phase. The S-shaped curve relates to overall growth patterns rather than specifically to respiratory activity.

5. **Conclusion**:
- Based on the evaluations, the correct answer is that both the assertion and the 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, and reason is not the correct explanation of assertion.**

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