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A cross made between two pea… (Class 10 Science 2024, Q12)

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ScienceCBSE Class 10 · Board exam 2024, set 31/2/1 · 1 mark · MCQ

CBSE Class 10 Science 2024: question 12

Set in the CBSE Class 10 board exam of 2024, paper 31/2/1, section A, question 12, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q12 · 1 mark · MCQHeredity

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

  1. (A) and
  2. (B) and
  3. (C) and
  4. (D) and

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 31/2/1.

Hints

Open one hint at a time and try again before the next.

Hint 1

A 1 : 1 ratio comes from crossing a heterozygous plant with a recessive plant.

Hint 2

Draw the cross for each option and check the ratio.

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

  1. Cross Tt × tt. The Tt parent gives gametes T and t; the tt parent gives only t.

    ½ mark

  2. Offspring are Tt (tall) and tt (short) in a 1 : 1 ratio, which is 50% tall and 50% short. Option (C) is correct.

    ½ mark

Answer: Tt and tt: option (C)

Where the marks are

  • Selects option (C) with 1 : 1 ratio reasoning (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Heredity, one at a time, marked against the answer key and marking points.Back to the full paper2024 board paper, set 31/2/1: every question, by section.

The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.