The correct sequence of phases of the cell-cycle is

Options

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

Answer

To determine the correct sequence of phases of the cell cycle, we need to understand the structure of the cell cycle itself. The cell cycle consists of two main phases: interphase and the mitotic (M) phase. Here’s a step-by-step breakdown of the phases:

### Step-by-Step Solution:

1. **Identify the Main Phases of the Cell Cycle**:
- The cell cycle is divided into two primary phases:
- Interphase
- M phase (Mitosis)

2. **Understand Interphase**:
- Interphase is the phase where the cell prepares for division and consists of three sub-phases:
- G1 phase (Gap 1)
- S phase (Synthesis)
- G2 phase (Gap 2)

3. **Order of Interphase Phases**:
- The correct order of the interphase phases is:
- G1 phase → S phase → G2 phase

4. **M Phase**:
- After interphase, the cell enters the M phase, which involves:
- Mitosis (division of the nucleus)
- Cytokinesis (division of the cytoplasm)

5. **Complete Sequence**:
- Therefore, the complete sequence of the cell cycle phases is:
- G1 phase → S phase → G2 phase → M phase

6. **Final Confirmation**:
- The correct sequence can be confirmed by checking the options provided in the question. The correct order is:
- G1 → S → G2 → M

### Conclusion:
The correct sequence of phases of the cell cycle is G1 phase, S phase, G2 phase, and M phase.

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