Assertion :- Chiasmata is the result of crossing over.
Reason:- Chiasmata arise during pachytene so that crossing over can take palce

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 solve the question regarding the assertion and reason, we will analyze both statements step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Chiasmata is the result of crossing over."
- This statement is true. Chiasmata are the physical manifestations of crossing over, where homologous chromosomes exchange genetic material during meiosis.

2. **Understanding the Reason**:
- The reason states that "Chiasmata arise during pachytene so that crossing over can take place."
- This statement is incorrect. Chiasmata do not arise during the pachytene stage; they actually form during the diplotene stage of prophase I in meiosis.

3. **Evaluating the Relationship**:
- Since the assertion is true and the reason is false, we need to determine the correct option based on this evaluation.

4. **Conclusion**:
- The correct answer is that the assertion is true but the reason is false. Therefore, the appropriate option would be the one that states "Assertion is true but reason is false."

### Final Answer:
The correct option is: **Assertion is true but reason is false.**

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