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

Options

A. Release of egg : `5th` day
B. Endometrium regenerates, `5 - 10` days
C. Endomeirium secretes nutrients for implantation : `11 - 18` days
D. rise in progesterone level : `4 - 15` days

Answer

To solve the question regarding the correctly matched event with the time period in a normal menstrual cycle, we will analyze the phases of the menstrual cycle and their corresponding durations.

### Step-by-Step Solution:

1. **Understand the Menstrual Cycle**: The normal menstrual cycle in human females typically lasts about 28 days and consists of four main phases: menstrual phase, follicular phase, ovulatory phase, and luteal phase.

2. **Identify the Phases**:
- **Menstrual Phase**: This phase lasts from day 1 to day 4, where bleeding occurs.
- **Follicular Phase**: This phase lasts from day 5 to day 13. During this time, follicles mature, and the endometrium begins to rebuild.
- **Ovulatory Phase**: This is a short phase that occurs on day 14, where ovulation takes place.
- **Luteal Phase (Secretory Phase)**: This phase lasts from day 15 to day 28. The corpus luteum forms, and progesterone is secreted to prepare the endometrium for potential implantation.

3. **Evaluate the Options**:
- **Option 1**: Release of egg on day 5 - Incorrect, as ovulation occurs on day 14.
- **Option 2**: Endometrium regeneration from day 5 to day 10 - Correct, as the endometrium rebuilds during the follicular phase (day 5 to day 13).
- **Option 3**: Endometrium secreting nutrients for implantation from day 11 to day 18 - Incorrect, as the secretion of nutrients occurs during the luteal phase (day 15 to day 28).
- **Option 4**: Rise in progesterone level from day 4 to day 15 - Incorrect, as progesterone levels rise after ovulation, peaking around day 23.

4. **Conclusion**: The only correct match is **Option 2**, which states that the endometrium regenerates from day 5 to day 10.

### Final Answer:
The correct option is **Option 2: Endometrium regeneration from day 5 to day 10**.

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