Read the following statements about cell division and select the correct ones.
(i) M phase represents the phase when actual cell division occurs and I phase represetns the phase between two successive M phases.
(ii) In the 24 hours average duration of cell cycle of a human cell, cell division proper lasts for only about an hour.
(iii) M phase constitutes more than 95% of the duration of cell cycle.

Options

A. i and ii
B. ii and iii
C. i and iii
D. i,ii and iii

Explanation

To determine which statements about cell division are correct, we need to analyze each statement based on our understanding of the cell cycle. Let's break it down step by step.

### Step 1: Understand the Cell Cycle Phases
The cell cycle consists of several phases:
- **G1 Phase (Gap 1)**: This phase lasts for about 6 to 12 hours and is primarily a growth phase where the cell prepares for DNA replication.
- **S Phase (Synthesis)**: This phase lasts for about 6 to 8 hours, during which DNA is replicated, changing from 2N to 4N.
- **G2 Phase (Gap 2)**: This phase lasts for about 3 to 4 hours, where the cell continues to grow and prepares for mitosis, with DNA remaining at 4N.
- **M Phase (Mitosis)**: This phase lasts for about 1 hour and is when actual cell division occurs, where the DNA is divided from 4N back to 2N.

### Step 2: Analyze Each Statement
Now, let's evaluate the statements provided in the question:

1. **Statement (i)**: "M phase represents the phase when actual cell division occurs and I phase represents the phase between two successive M phases."
- **Analysis**: This statement is correct. The M phase is indeed when cell division occurs, and the interphase (I phase) is the time between two M phases.

2. **Statement (ii)**: "In the 24 hours average duration of cell cycle of a human cell, cell division proper lasts for only about an hour."
- **Analysis**: This statement is also correct. The M phase lasts for approximately 1 hour, while the rest of the cell cycle takes about 23 hours.

3. **Statement (iii)**: "M phase constitutes more than 95% of the duration of the cell cycle."
- **Analysis**: This statement is incorrect. Since the M phase lasts for about 1 hour, it constitutes roughly 5% of the cell cycle duration, not more than 95%.

### Conclusion
Based on the analysis:
- **Correct Statements**: (i) and (ii)
- **Incorrect Statement**: (iii)

Thus, the correct answer is that statements (i) and (ii) are correct.