[A]: Exchange of genetic material occurs during meiosis.
[R]: There is chiasma formation in meiosis.

Options

A. If both A and R are true and R is the correct explanation of A
B. If both A and R are true but R is not the correct explanation of A
C. If A is true and R is false
D. If both A and R are false

Answer

**Step-by-Step Solution:**

1. **Understanding the Statements**: The question presents two statements:
- [A]: Exchange of genetic material occurs during meiosis.
- [R]: There is chiasma formation in meiosis.

2. **Analyzing Statement A**:
- Meiosis is a type of cell division that reduces the chromosome number by half, resulting in four haploid cells from one diploid cell.
- During meiosis, particularly in prophase I, homologous chromosomes pair up and exchange genetic material through a process known as crossing over.

3. **Analyzing Statement R**:
- Chiasma formation refers to the points where homologous chromosomes exchange genetic material during crossing over.
- This process is crucial for genetic diversity as it allows for the recombination of genetic material.

4. **Conclusion on the Truth of Statements**:
- Both statements A and R are true.
- Statement R (chiasma formation) is indeed the mechanism through which the exchange of genetic material occurs during meiosis.

5. **Final Answer**:
- Both A and R are true, and R is the correct explanation of A.

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