Q1. [1] § Introduction § 8.2.2 Rules for the Inheritance of Traits – Mendel's Contributions
A cross made between two pea plants produces 50% tall and 50% short pea plants. The gene combination of the parental pea plants must be
- (A) Tt and Tt
- (B) TT and Tt
- (C) Tt and tt
- (D) TT and tt
Previously asked in CBSE board exam
2024 31/2/1 Q12
Generated by claude-sonnet-4-6 · 2026-06-15 06:53 · grounding rag
Model Answer
(C) Tt and tt
When Tt × tt cross is performed, offspring are 50% Tt (tall) and 50% tt (short), matching the given result.
Explanation
This is a test cross (tall heterozygous × short homozygous recessive). Option A (Tt × Tt) gives 75% tall : 25% short; Option B gives all tall or 3:1; Option D gives all tall. Only Tt × tt produces the 1:1 ratio (50:50) described. Examiners expect you to recall basic monohybrid cross ratios.
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