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Science · 2025 · 4 marks
CBSE 2025 · Region 2 · Set 1 · Q38
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…
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.
(a)
Write the site of fertilization in human female.
(b)
How does the uterus prepare itself to receive and nurture the growing embryo ? Explain.
(c)(i)
What happens when the egg is not fertilized ?
OR
(c)
(ii)
How does the developing embryo get nutrition from the mother's blood? Explain.
Marking-scheme solution
(a) Oviduct/ fallopian tube
(b) The lining of uterus thickens (it becomes spongy) and is richly supplied with blood to nourish the growing embryo.
(c) (i) The uterine lining slowly breaks down and comes out as blood and mucous along with unfertilized egg. Hence, menstruation will occur.
(c)
With the help of special tissue called Placenta which is embedded in uterine wall. It provides oxygen, nutrients from mother to embryo.
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CBSE Class 10 Science past-paper question from the 2025 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.