Define the term synapsis. Name the stage of cell cycle when it occurs.

Explanation

**Step-by-Step Solution:**

1. **Define Synapsis:**
- Synapsis is the process during which homologous chromosomes pair up during meiosis. This pairing occurs between a maternal chromosome and its corresponding paternal chromosome, forming a structure known as a bivalent or tetrad.

2. **Identify the Stage of Cell Cycle:**
- Synapsis occurs during the zygotene stage of prophase I in meiosis. This is a crucial part of the cell cycle where genetic recombination can take place, leading to genetic diversity in the resulting gametes.

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