The sequence of cell cycle is

Options

A. S, M, `G_(1)`, and `G_(2)`
B. `G_(1), G_(2)`, S and M
C. M, `G_(1), G_(2)`, and S
D. `G_(1)`, S, `G_(2)`, and M

Answer

To determine the correct sequence of the cell cycle, we can break down the phases involved in the cell cycle step by step.

### Step-by-Step Solution:

1. **Identify the Phases of the Cell Cycle**:
The cell cycle consists of several phases: G1 (Gap 1), S (Synthesis), G2 (Gap 2), and M (Mitosis).

2. **Understanding Each Phase**:
- **G1 Phase**: This is the first phase where the cell grows and synthesizes proteins necessary for DNA replication. The cellular contents, excluding the chromosomes, are duplicated.
- **S Phase**: During this phase, DNA replication occurs. Each chromosome is duplicated, resulting in two sister chromatids for each chromosome.
- **G2 Phase**: In this phase, the cell continues to grow and produces proteins necessary for mitosis. It also checks for any errors in the duplicated DNA.
- **M Phase**: This is the phase where mitosis occurs, leading to the division of the cell into two daughter cells.

3. **Correct Sequence**:
The correct sequence of the cell cycle is G1 → S → G2 → M.

4. **Evaluate the Options**:
- Option 1: S, M, G1, G2 (Incorrect)
- Option 2: G1, G2, S, M (Incorrect)
- Option 3: M, G1, G2, S (Incorrect)
- Option 4: G1, S, G2, M (Correct)

### Final Answer:
The correct sequence of the cell cycle is **G1, S, G2, M** (Option 4).

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