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Science — CBSE Class 10 board question

Q1. [1]
A cross between pea plant with white flowers (vv) and pea plant with violet flowers (VV) resulted in F2 progeny in which ratio of violet (VV) and white (vv) flowers will be :
  1. (a) 1 : 1
  2. (b) 2 : 1
  3. (c) 3 : 1
  4. (d) 1 : 3
Previously asked in CBSE board exam
2023 31/4/1 Q10
Generated by claude-sonnet-4-6 · 2026-06-15 06:52 · grounding rag
Model Answer

(c) 3 : 1

Cross: vv × VV → F1 all Vv (violet). F1 × F1: VV : Vv : vv = 1:2:1, so violet (VV + Vv) : white (vv) = 3 : 1.

Explanation

The cross vv × VV gives all Vv in F1. F2 from Vv × Vv gives 1VV : 2Vv : 1vv. Since V is dominant, both VV and Vv show violet flowers — so violet : white = 3 : 1. This is the classic Mendelian monohybrid ratio. Examiners expect you to pick option (c) and ideally know why (F1 × F1 logic).

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Previous-year CBSE Grade 10 board exam questions, organised by subject and chapter, each with a model answer — free to read and print.