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Science · 2026 · 3 marks
CBSE 2026 · Region 2 · Set 1 · Q14
(a) Giving two examples, justify the statement that the sex of the offspring in all animals is not always genetically determined. (b) Differentiate…
(a)
Giving two examples, justify the statement that the sex of the offspring in all animals is not always genetically determined.
(b)
Differentiate between the sex chromosomes of male and female human beings.
Marking-scheme solution
(a)
In a few reptiles, the temperature at which fertilised eggs
are kept determine whether the animal developing from
the eggs will be male or female.
In snails, individuals can change sex.
(b)
| Male sex chromosome | Female sex chromosome |
| Male has a mismatched pair i.e, 'XY' chromosomes. | Female has a perfect pair i.e. 'XX' chromosomes. |
| Y chromosome is smaller than X chromosome. | Both X chromosomes are of same size. |
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CBSE Class 10 Science past-paper question from the 2026 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.