Assertion :- Rough endoplasmic reticulum is the precursor of smooth endoplasmic reticulum.
Reason:- Smooth endoplasmic reticulum arises from endoplasmic reticulum after detechment of ribosomes

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 is False
D. If both Assertion & Reason are false.

Answer

To analyze the assertion and reason provided in the question, we can break down the statements step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Rough endoplasmic reticulum (RER) is the precursor of smooth endoplasmic reticulum (SER)."
- This means that RER gives rise to SER.

2. **Understanding the Reason**:
- The reason states that "Smooth endoplasmic reticulum arises from endoplasmic reticulum after detachment of ribosomes."
- This indicates that SER forms when ribosomes detach from the RER.

3. **Connecting Assertion and Reason**:
- RER is characterized by the presence of ribosomes on its surface, which gives it a "rough" appearance.
- When these ribosomes detach, the structure can transition into SER, which lacks ribosomes and is involved in lipid synthesis and detoxification processes.

4. **Evaluating the Truth of Both Statements**:
- Both the assertion and reason are true based on cellular biology.
- The reason correctly explains how SER is formed from RER by the detachment of ribosomes.

5. **Conclusion**:
- Since both the assertion and reason are true, and the reason provides a correct explanation for the assertion, we can conclude that the correct answer is that both statements are true and the reason is the correct explanation of the assertion.

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

---