Parental chromosome produce two identical sister chromatids during

Options

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

Answer

**Step-by-Step Solution:**

1. **Understand the Cell Cycle:**
- The cell cycle is a series of events that cells go through as they grow and divide. It consists of interphase and the mitotic phase (M phase).

2. **Identify the Phases of Interphase:**
- Interphase is divided into three sub-phases: G1 phase (Gap 1), S phase (Synthesis), and G2 phase (Gap 2).
- G1 phase is primarily focused on cell growth and preparation for DNA synthesis.
- G2 phase involves further growth and preparation for mitosis.

3. **Focus on the S Phase:**
- The S phase is where DNA replication occurs. During this phase, each parental chromosome is duplicated.
- As a result of DNA replication, each chromosome produces two identical sister chromatids.

4. **Eliminate Other Options:**
- G1 phase does not involve DNA replication; it is mainly for growth.
- G2 phase also does not involve DNA replication; it is for further growth and preparation for cell division.
- Prophase is part of the M phase, where the cell begins to divide, but DNA replication has already occurred.

5. **Conclusion:**
- The correct answer to the question is that parental chromosomes produce two identical sister chromatids during the **S phase**.

**Final Answer: S phase**

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