Assertion (A): Sexual reproduction increases genetic diversities and plays a role in origin of new species.
Reason ( R): Sexual reproduction involves formation of gametes and fusion of gametes.

Options

A. Both A and R are true and R is the correct explanation of A.
B. Both A and R are true but R is NOT the correct explanation of A.
C. A is true but R is false.
D. A is false and R is true.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Assertion (A)**: The assertion states that sexual reproduction increases genetic diversity and plays a role in the origin of new species. This is true because sexual reproduction involves the combination of genetic material from two parents, leading to offspring that have unique genetic combinations.

2. **Understanding the Reason (R)**: The reason states that sexual reproduction involves the formation of gametes and the fusion of these gametes. This is also true, as sexual reproduction requires male and female gametes (sperm and egg) to come together to form a zygote.

3. **Linking Assertion and Reason**: The assertion is supported by the reason. The process of gamete formation and fusion is fundamental to sexual reproduction, which in turn leads to genetic diversity. The mixing of genetic material from two parents results in variations in traits among offspring, contributing to genetic diversity and the potential for new species to arise over time.

4. **Conclusion**: Since both the assertion and reason are true, and the reason correctly explains the assertion, the correct answer is that both assertion and reason are true, and the reason is the correct explanation of the assertion.

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

---