M phase of cell cycle starts with

Options

A. Duplication of DNA
B. Karyokinesis
C. Cytokinesis
D. Division of chromosomes

Answer

To answer the question "M phase of cell cycle starts with," we need to analyze the options provided and understand the phases of the cell cycle.

### Step-by-Step Solution:

1. **Understanding the M Phase**:
- The M phase, or mitotic phase, is the part of the cell cycle where cell division occurs. It includes both mitosis (the division of the nucleus) and cytokinesis (the division of the cytoplasm).

2. **Evaluating the Options**:
- **Duplication of DNA**: This occurs during the S phase of the cell cycle, not the M phase. Therefore, this option is incorrect.
- **Karyokinesis**: This is the process of nuclear division that occurs during the M phase. It is the first step in the M phase where the chromosomes are separated into two nuclei. This option is likely correct.
- **Cytokinesis**: This is the division of the cytoplasm that usually follows karyokinesis. Since it occurs after the nucleus has divided, this option is incorrect for the start of the M phase.
- **Division of Chromosomes**: This process occurs during karyokinesis, specifically during the metaphase and anaphase stages of mitosis. However, it is not the starting point of the M phase itself. Therefore, this option is also incorrect.

3. **Conclusion**:
- Based on the analysis, the M phase of the cell cycle starts with **karyokinesis**.

### Final Answer:
The M phase of the cell cycle starts with **karyokinesis**.

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