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Science · 2025 · 5 marks
CBSE 2025 · Region 4 · Set 3 · Q35
(A) Name the parts marked as 'A' and 'B' in the given diagram. Write in detail the changes that take place in a flower when the product of 'B'…
Name the parts marked as 'A' and 'B' in the given diagram. Write in detail the changes that take place in a flower when the product of 'B' reaches 'A' till a
fruit is formed.
In human female reproductive system state the changes that take place once fertilisation has taken place. Write the role of placenta in this process. What happens when the egg is not fertilised ?
Marking-scheme solution
A - Stigma ; B - Anther - pollen germinate to form pollen tube which carries male germ cells to the egg cell in the ovule of the ovary. - Fusion of germ cells/fertilization gives rise to zygote. - Zygote divides to form an embryo within the ovule. Ovule develops and converted into a seed. - Ovary grows rapidly to form a fruit. Petals, sepals, stamens, style, etc. shrivel and fall off.
Changes after fertilization: - Fertilisation results in the formation of a zygote. - Zygote starts dividing to form an embryo, which is implanted in the lining of the uterus. - Embryo continues to grow and derive nutrition through placenta. Role of placenta To provide oxygen and glucose to the embryo from mother's blood To remove waste substances generated by the developing embryo. If the egg is not fertilized: - the lining of the uterus slowly breaks and comes out through the vagina as blood and mucous./ menstruation will occur.
All How do Organisms Reproduce? questions2025 question paperNCERT solutions: How do Organisms Reproduce?Practice How do Organisms Reproduce? →
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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.