CBSE 2024 · Region 4 · Set 2 · Q22 · 3 marks
With reference to flower colour two independent crosses were made, one between true breeding garden pea plants and another between true breeding Antirrhinum plants. Write the phenotypes of their $\displaystyle \mathrm{F}_{1}$-progeny. Justify your answer giving reason.
Marking-scheme solution
Garden pea (complete dominance): PP (Violet) × pp (White) → Pp — all purple flowers. Antirrhinum / snapdragon (incomplete dominance): RR (Red) × rr (White) → Rr — all pink flowers. The F₁ phenotypes differ because pea shows complete dominance while Antirrhinum shows incomplete dominance.
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CBSE Class 12 Biology past-paper question from the 2024board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.