What happens in crossing over :-

Options

A. Duplication of chromosomes
B. Linkage in chromosomes
C. Minimization in genetic material
D. Exchange of genetic material

Answer

**Step-by-Step Solution:**

1. **Understanding Crossing Over**: Crossing over is a process that occurs during meiosis, specifically in prophase I, where homologous chromosomes exchange genetic material.

2. **Identifying the Options**: The question provides four options regarding what happens during crossing over:
- A) Duplication of chromosomes
- B) Linkage in chromosomes
- C) Minimization in genetic material
- D) Exchange of genetic material

3. **Analyzing Each Option**:
- **Option A (Duplication of chromosomes)**: This is incorrect because chromosome duplication occurs during the synthesis phase (S phase) of the cell cycle, not during crossing over.
- **Option B (Linkage in chromosomes)**: This is also incorrect. Linkage refers to the tendency of genes located close together on a chromosome to be inherited together, but it does not describe what happens during crossing over.
- **Option C (Minimization in genetic material)**: This option is incorrect as well. Crossing over does not minimize genetic material; rather, it allows for genetic variation.
- **Option D (Exchange of genetic material)**: This is the correct answer. During crossing over, segments of DNA are exchanged between non-sister chromatids of homologous chromosomes, leading to genetic variation.

4. **Visual Representation**: In crossing over, a structure called chiasmata forms where the chromosomes physically overlap and exchange segments of genetic material.

5. **Conclusion**: The correct answer to the question "What happens in crossing over?" is the exchange of genetic material.

**Final Answer**: D) Exchange of genetic material.

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