In cell cycle, DNA replication occurs during

Options

A. `G_(1)` phase
B. `G_(2)` phase
C. metaphase
D. S phase

Answer

**Step-by-Step Solution:**

1. **Understanding the Cell Cycle**: The cell cycle is divided into two main phases: Interphase (I phase) and Mitotic phase (M phase).

2. **Phases of Interphase**: Interphase is further divided into three sub-phases:
- G1 phase (Gap 1)
- S phase (Synthesis)
- G2 phase (Gap 2)

3. **Identifying DNA Replication Phase**:
- During the G1 phase, the cell prepares for DNA replication by synthesizing proteins and enzymes necessary for the process.
- The actual DNA replication occurs during the S phase. This is where the synthesis of DNA takes place, which is why it is referred to as the "S phase."

4. **Post-DNA Replication Preparation**: After DNA replication in the S phase, the G2 phase involves preparation for cell division, which will occur in the M phase.

5. **Conclusion**: Therefore, the correct answer to the question "In cell cycle, DNA replication occurs during" is the S phase.

**Final Answer**: DNA replication occurs during the S phase of the cell cycle.

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