PYQ Vault

Day 40: CBSE Class 10 Science

5 questions (8 parts). Try each one first, then open its answer.

  1. Question 1

    Heredity. This type asked 4 times: 2022, 2023, 2025, 2026. This one: 2026

    Two statements are given, one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer from the options given below.
    8
    Assertion (A) : Bacteria that can withstand heat have better chances of survival in a heat wave. Reason (R) : Accumulation of variations in a species increases the chances of its survival in changing environment.

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  2. Question 2

    Heredity. This type asked 4 times: 2023, 2024, 2025, 2026. This one: 2026

    1
    The genotype of green stemmed tomato plant is denoted by ‘GG’ and that of purple stemmed tomato plant as ‘gg’. Hybrid of a cross between these two were self-pollinated to obtain F2\text{F}_2 progeny. What will be the ratio of GG, Gg and gg in this F2\text{F}_2 progeny ?

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  3. Question 3

    Heredity. This type asked 4 times: 2022, 2024, 2025, 2026. This one: 2026

    13
    Use the following information for Pea plants : Dominant allele for tall plants – T Recessive allele for short plants – t Dominant allele for purple flowers – P Recessive allele for white flowers – p (a) Perform a cross between pure plant dominant for both the traits with another plant which is recessive for both the traits and work out the progeny upto F2\mathrm{F_2} generation. (b) What is the probability of obtaining tall plants with white flowers in F2\mathrm{F_2} progeny ?

  4. Question 4 (case study, 4 parts)

    Heredity. This type asked 4 times: 2022, 2023, 2024, 2026. This one: 2026

    Mendel took garden pea plants with different characteristics, such as height to study the inheritance pattern of factors (genes). He crossed tall pea plant with short pea plant and obtained all the tall plants in the F1\mathrm{F_1} generation.
    15 (a)
    Why only tall pea plants were observed in F1\mathrm{F_1} progeny ?
    15 (b)
    By which method did Mendel obtain F2\mathrm{F_2} progeny ?
    15 (c) (i)
    Write one difference between dominant and recessive trait.
    15 (c) (ii)
    Write two observations made by Mendel about F1\mathrm{F_1} progeny.

  5. Question 5

    How do Organisms Reproduce?. This type asked 4 times: 2023, 2024, 2025, 2026. This one: 2026

    3
    A farmer wants to grow banana plants genetically similar to the plants already available in the fields. Which of the following method would you suggest for this purpose :

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