When a girl is born, the ovaries already contain thousands of immature eggs. On reaching puberty, some of these start maturing. One matured egg is released every month by one of the ovaries. The two oviducts unite into an elastic bag-like structure known as uterus.
Read the case carefully and answer the questions that follow.
Generated by claude-sonnet-4-6 · 2026-06-15 06:42 · grounding stimulus
Model Answer
(a) The site of fertilization in the human female is the fallopian tube (oviduct).
(b) The uterus prepares itself by developing a thick and spongy lining richly supplied with blood vessels. This lining nourishes the embryo and provides it with oxygen and nutrients for development.
(c)(i) If the egg is not fertilized, it lives for about one day. The uterus lining, which was prepared to receive the embryo, is no longer needed. The lining slowly breaks down and is shed along with the unfertilized egg in the form of blood and mucus through the vagina. This is called menstruation, which lasts for about 2–8 days.
Source: Chapter – How do Organisms Reproduce?, Section – Reproduction in Human Beings
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Explanation
- (a) One line is enough — "oviduct/fallopian tube" is the key term.
- (b) Focus on the uterine lining becoming thick and blood-vessel-rich; that's the examiner's expected detail.
- (c)(i) The 2-mark answer must cover two points: (i) the egg is not fertilised and degenerates, and (ii) the uterine lining breaks down → menstruation. Mentioning the term menstruation is essential for full marks.