OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

During which days of the menstrual cycle does the uterus lining rebuild?

1. Days 1-3

2. Days 4-14

3. Days 15-21

4. Days 22-28

The correct answer is: Days 4-14

The correct timeframe for the rebuilding of the uterus lining in the menstrual cycle is from day 4 to day 14, which corresponds to the follicular phase. After menstruation occurs, the menstrual phase (days 1-3) involves the shedding of the uterine lining. Once this phase is over, the body begins a new cycle of rebuilding the endometrium in preparation for a potential pregnancy. During days 4 to 14, the hormone estrogen rises, stimulating the growth and thickening of the endometrial lining. This process ensures that the uterus is well-prepared to support a fertilized egg should conception occur. The activity that takes place in this stage is crucial for reproductive health, as the thickened lining creates an optimal environment for implantation. The subsequent phases of the cycle involve different hormonal changes and processes, which are not involved in the rebuilding of the lining. Therefore, days 4 to 14 is the correct and critical window for the rebuilding of the uterus lining during the menstrual cycle.