Assertion :- M-phase is the most dramatic period of the cell cycle.
Reason :- It involves a major reorganisation of virtually all components of the cell.

Options

A. If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion.
B. If both Assertion & Reason are True but Reason is not a correct explanation of the Assertion.
C. If Assertion is True but the Reason is False.
D. If both Assertion & Reason are false.

Answer

To analyze the assertion and reason provided in the question, let's break it down step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "M-phase is the most dramatic period of the cell cycle."
- The M-phase, or mitotic phase, is indeed known for the significant changes that occur as the cell prepares to divide.

2. **Understanding the Reason**:
- The reason states that "It involves a major reorganization of virtually all components of the cell."
- During the M-phase, several key processes occur, including the condensation of chromatin into chromosomes, breakdown of the nuclear envelope, and the reorganization of the cytoskeleton to form the mitotic spindle.

3. **Analyzing the Relationship**:
- The assertion is true because the M-phase is characterized by dramatic changes.
- The reason is also true because the M-phase does involve a major reorganization of cellular components, including DNA and organelles.

4. **Determining the Correct Option**:
- Since both the assertion and reason are true, and the reason correctly explains why the M-phase is considered the most dramatic period, the correct option is:
- **Option A**: Both assertion and reason are true, and the reason is the correct explanation of the assertion.

### Final Answer:
The correct answer is **Option A**: Both assertion and reason are true, and the reason is the correct explanation of the assertion.

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