DNA replication takes place at ________ phase the cell cycle.

Options

A. `G_1`
B. S
C. `G_2`
D. M

Explanation

**Step-by-Step Solution:**

1. **Understanding the Cell Cycle**: The cell cycle consists of several phases: G1 (Gap 1), S (Synthesis), G2 (Gap 2), and M (Mitosis). Each phase has specific functions related to cell growth and division.

2. **Identifying the S Phase**: The S phase is specifically designated for DNA synthesis. During this phase, the cell replicates its DNA, ensuring that each daughter cell will receive an identical set of chromosomes.

3. **Role of DNA Replication**: DNA replication is crucial for cell division. It ensures that genetic information is accurately copied and passed on to the next generation of cells.

4. **Coordinated Events**: The process of DNA replication must be coordinated with the overall cell cycle to ensure proper cell division. If DNA replication occurs without subsequent cell division, it can lead to issues such as aneuploidy (abnormal number of chromosomes).

5. **Conclusion**: Based on the understanding of the cell cycle and the specific role of the S phase, we conclude that DNA replication takes place during the S phase of the cell cycle.

**Final Answer**: DNA replication takes place at the S phase of the cell cycle.

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