In a dividing somatic cell, which one of the following stage is diploid ?

Options

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

Explanation

To determine which stage of a dividing somatic cell is diploid, we need to analyze the different stages of the cell cycle: G1, S, G2, and M phases.

### Step-by-Step Solution:

1. **Understanding Somatic Cells**:
- Somatic cells are body cells that are not involved in reproduction. They are typically diploid (2n), meaning they contain two sets of chromosomes—one set from each parent.

2. **Identifying the Stages of the Cell Cycle**:
- The cell cycle consists of several stages:
- **G1 Phase (Gap 1)**: The cell grows and carries out normal functions. At this stage, the cell is diploid (2n).
- **S Phase (Synthesis)**: DNA replication occurs, resulting in the duplication of chromosomes. At the end of this phase, the cell has twice the amount of DNA, becoming tetraploid (4n).
- **G2 Phase (Gap 2)**: The cell continues to grow and prepares for mitosis. The DNA is still in a duplicated state (tetraploid, 4n).
- **M Phase (Mitosis)**: The cell divides into two daughter cells. Each daughter cell will have a diploid set of chromosomes (2n) after division.

3. **Analyzing Each Option**:
- **Option A (G1)**: The cell is diploid (2n) at this stage.
- **Option B (G2)**: The cell is tetraploid (4n) due to DNA replication.
- **Option C (S Phase)**: The cell is also tetraploid (4n) as DNA is being replicated.
- **Option D (M Phase)**: While the daughter cells will be diploid after division, during the actual process of mitosis, the cell is still in a tetraploid state until division is complete.

4. **Conclusion**:
- The only stage where the dividing somatic cell is diploid is the G1 phase. Therefore, the correct answer is **Option A (G1)**.

### Final Answer:
**The diploid stage in a dividing somatic cell is G1 phase (Option A).**

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