Crossing over takes place during which phase of meiosis?

Options

A. Zygotene stage
B. Pachytene stage
C. Diakinesis stage
D. Leptotene stage

Answer

**Step-by-Step Solution:**

1. **Understanding Meiosis:** Meiosis is a type of cell division that reduces the chromosome number by half and is essential for sexual reproduction. It consists of two main stages: Meiosis I and Meiosis II.

2. **Identifying Phases of Meiosis I:** Meiosis I is further divided into several phases: Prophase I, Metaphase I, Anaphase I, and Telophase I. The focus here is on Prophase I, which is subdivided into several stages: Leptotene, Zygotene, Pachytene, Diplotene, and Diakinesis.

3. **Defining Crossing Over:** Crossing over is the process where homologous chromosomes exchange segments of genetic material. This exchange occurs between non-sister chromatids of homologous chromosomes, leading to genetic variation in the resulting gametes.

4. **Locating Crossing Over in Meiosis:** Crossing over specifically occurs during the Pachytene stage of Prophase I. During this stage, homologous chromosomes are closely aligned, allowing for the exchange of genetic material.

5. **Conclusion:** Therefore, the correct answer to the question "Crossing over takes place during which phase of meiosis?" is the Pachytene stage of Prophase I.

**Final Answer:** Crossing over takes place during the Pachytene stage of meiosis.

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