CBSE 2025 · Region 7 · Set 1 · Q15 · 1 mark
Assertion (A) : A male individual always inherits haemophilia from his mother.
Reason (R) : The gene for haemophilia lies on X-chromosome.
Official answer
From CBSE’s own marking scheme for this paper.
(A)
Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
Principles of Inheritance and VariationSex DeterminationUnderstandassertion_reasonmedium
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CBSE Class 12 Biology past-paper question from the 2025board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.