Assertion: The crossing over is an enzyme-mediated process.
Reason: The enzyme involved in crossing over is lyase.

Options

A. If both assertion and reason are true and reason is the correct explantion of assertion
B. If both assertion and reason are true but reason is not the correct explnantion of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Assertion:**
- The assertion states that "the crossing over is an enzyme-mediated process."
- Crossing over is a biological process that occurs during meiosis where homologous chromosomes exchange genetic material. This process is crucial for genetic diversity.

2. **Understanding the Reason:**
- The reason provided is that "the enzyme involved in crossing over is lyase."
- This statement is misleading. While enzymes are indeed involved in crossing over, the specific enzyme mentioned (lyase) is not the correct one for this process.

3. **Identifying the Correct Enzymes:**
- During crossing over, the process involves two main steps: breakage of genetic material and rejoining.
- The enzyme responsible for the breakage of DNA strands is called **endonuclease**.
- The enzyme responsible for rejoining the DNA strands is called **ligase**.

4. **Evaluating the Assertion and Reason:**
- Since the assertion is true (crossing over is enzyme-mediated), but the reason is false (the enzyme involved is not lyase but ligase), we conclude that:
- The assertion is true, and the reason is false.

5. **Conclusion:**
- Based on the evaluation, the correct answer is that the assertion is true, but the reason is false.

**Final Answer:**
- The correct option is: Assertion is true, but the reason is false.

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