Though the total number of follicles in the ovaries of a nomal young woman is about 4,00,000 the duration between menarche and menopause is limited. This is attributed to the
(a) follicular atresia
(b) liquor folliculi
(c) follicular proliferation
(d) follicular plasticity

Options

A. follicular atresia
B. liquor folliculi
C. follicular proliferation
D. follicular plasticity

Answer

To solve the question, we need to understand the factors that influence the number of follicles in the ovaries of a normal young woman and the duration between menarche (the first menstrual period) and menopause (the end of menstrual cycles).

### Step-by-Step Solution:

1. **Understanding Follicles**: A normal young woman has about 400,000 follicles in her ovaries at the start of her reproductive life. These follicles contain oocytes (immature eggs) and are crucial for reproduction.

2. **Menarche and Menopause**: The reproductive phase of a woman begins with menarche and ends with menopause. This phase is limited in duration, typically spanning several decades.

3. **Follicular Atresia**: This term refers to the process by which ovarian follicles undergo degeneration and are reabsorbed by the body. Not all follicles will mature into eggs; many will undergo atresia, leading to a decrease in the number of available follicles over time.

4. **Impact of Follicular Atresia**: Because of follicular atresia, the number of viable follicles decreases throughout a woman's reproductive life. This is a significant factor that limits the duration of the reproductive phase, as the total number of follicles decreases until menopause is reached.

5. **Evaluating Options**:
- (a) Follicular atresia: Correct, as it explains the breakdown of follicles leading to a limited number of reproductive years.
- (b) Liquor folliculi: Incorrect, as this refers to the fluid within the follicle and does not relate to the number of follicles.
- (c) Follicular proliferation: Incorrect, as this refers to the growth of follicles, not their reduction.
- (d) Follicular plasticity: Incorrect, as this term does not directly relate to the limitation of reproductive years.

6. **Conclusion**: The correct answer is (a) follicular atresia, as it directly explains the limited duration between menarche and menopause due to the breakdown of ovarian follicles.

### Final Answer:
(a) follicular atresia