Which one of the following events is correctly matched with the time period in a normal menstrual cycle?

Options

A. Release of egg, `5^(th)` day
B. Endometrium regenerates: 5-10 days
C. Endometrium secretes nutrients for implantation: 11-18 days
D. Rise in progesterone level: 1-15 days

Answer

To solve the question of which event is correctly matched with the time period in a normal menstrual cycle, let's analyze each option step by step.

### Step-by-Step Solution:

1. **Understanding the Menstrual Cycle**:
- A normal menstrual cycle lasts about 28 days and consists of several phases: menstrual phase, proliferative phase, ovulatory phase, and luteal phase.

2. **Analyzing Each Option**:
- **Option A: Release of egg on the 5th day**:
- This is incorrect. The release of the egg (ovulation) typically occurs around the 14th day of the cycle, not the 5th day.

- **Option B: Endometrium regenerates from 5th to 10 days**:
- This is partially correct but not fully accurate. The regeneration of the endometrium occurs during the proliferative phase, which lasts from the 5th to the 13th day, not just the 5th to the 10th day.

- **Option C: Endometrium secretes nutrients for implantation from 11 to 18 days**:
- This is correct. After ovulation, during the luteal phase (approximately from the 11th to the 18th day), the endometrium prepares for potential implantation by secreting nutrients.

- **Option D: Rise in progesterone level from 1st to 15th day**:
- This is incorrect. The rise in progesterone levels occurs after ovulation, typically from the 15th to the 27th day of the cycle.

3. **Conclusion**:
- The only option that is correctly matched with the time period in a normal menstrual cycle is **Option C**: "Endometrium secretes nutrients for implantation from 11 to 18 days."

### Final Answer:
**Option C** is the correct answer.

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