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 in the cell cycle, we can break down the process step by step:

### Step 1: Understand the Phases of the Cell Cycle
The cell cycle consists of several phases:
1. **G1 Phase (Gap 1)**: This is the first phase where the cell grows and prepares for DNA replication.
2. **S Phase (Synthesis)**: In this phase, DNA is replicated, resulting in two copies of each chromosome.
3. **G2 Phase (Gap 2)**: The cell continues to grow and prepares for mitosis by synthesizing proteins and organelles.
4. **M Phase (Mitosis)**: This is the phase where the cell divides into two daughter cells.

### Step 2: Identify the Sequence
The sequence of the phases in the cell cycle is:
- G1 → S → G2 → M

### Step 3: Consider the G0 Phase
After M phase, a cell can either re-enter the G1 phase or enter the G0 phase (a resting or quiescent state). However, for the purpose of identifying the sequence of the cell cycle phases, we focus on G1, S, G2, and M.

### Step 4: Conclusion
The correct sequence of the phases of the cell cycle is:
- G1 → S → G2 → M

### Final Answer
The correct sequence of phases of the cell cycle is G1, S, G2, M.

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