This phase of cell cycle is a period of intense synthesis and growth. It constitutes 95% of the duration of cell cycle. It is

Options

A. interphase
B. telophase
C. prophase
D. anaphase.

Explanation

To solve the question regarding which phase of the cell cycle is a period of intense synthesis and growth, and constitutes 95% of the duration of the cell cycle, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Cell Cycle**: The cell cycle consists of several phases including interphase and mitotic phases (M phase). Interphase is where the cell spends most of its time preparing for division.

2. **Identify the Phases of Interphase**: Interphase is divided into three sub-phases:
- **G1 Phase (Gap 1)**: The cell grows and synthesizes proteins necessary for DNA replication.
- **S Phase (Synthesis)**: The cell replicates its DNA, ensuring that each daughter cell will have an identical set of chromosomes.
- **G2 Phase (Gap 2)**: The cell continues to grow and prepares for mitosis.

3. **Determine the Duration of Each Phase**: Interphase constitutes about 95% of the total cell cycle duration. In contrast, the M phase (which includes prophase, metaphase, anaphase, and telophase) only makes up about 5% of the cell cycle.

4. **Analyze the Options Given**: The options provided are:
- 1. Interphase
- 2. Telophase
- 3. Prophase
- 4. Anaphase

5. **Select the Correct Answer**: Since interphase is the phase where the cell undergoes intense synthesis and growth and constitutes 95% of the cell cycle, the correct answer is **Interphase**.

### Final Answer:
The phase of the cell cycle that is a period of intense synthesis and growth, constituting 95% of the duration of the cell cycle, is **Interphase**.

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