PYQ Vault

Day 77: CBSE Class 10 Science

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

  1. Question 1

    Heredity. Asked once: 2025 (same type asked 4 times)

    Two statements are given, one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer from the options given below.
    18
    Assertion (A) : A human child bears all the basic features of human beings. Reason (R) : It looks exactly like its parents, showing very little variations.

    Tap an option to check your answer.

  2. Question 2

    Heredity. Asked once: 2025 (same type asked 4 times)

    9
    When a pure-tall pea plant is crossed with a pure-dwarf pea plant, the percentage of tall pea plants in F1\mathrm{F_1} and F2\mathrm{F_2} generation pea plants will be respectively :

    Tap an option to check your answer.

  3. Question 3

    Heredity. Asked once: 2025 (same type asked 4 times)

    8
    A tall pea plant with round seeds (TTRR) is crossed with a short pea plant with wrinkled seeds (ttrr). The F1\mathrm{F_1} generation will be

    Tap an option to check your answer.

  4. Question 4 (case study, 4 parts)

    Heredity. Asked once: 2024 (same type asked 4 times)

    Mendel worked out the rules of heredity by working on garden pea using a number of visible contrasting characters. He conducted several experiments by making a cross with one or two pairs of contrasting characters of pea plant. On the basis of his observations he gave some interpretations which helped to study the mechanism of inheritance.
    38 (i)
    When Mendel crossed pea plants with pure tall and pure short characteristics to produce F1\mathrm{F_1} progeny, which two observations were made by him in F1\mathrm{F_1} plants?
    38 (ii)
    Write one difference between dominant and recessive trait.
    38 (iii) (A)
    In a cross with two pairs of contrasting characters RRYY ×\times rryy (Round Yellow) (Wrinkled Green) Mendel observed 4 types of combinations in F2\mathrm{F_2} generation. By which method did he obtain F2\mathrm{F_2} generation ? Write the ratio of the parental combinations obtained and what conclusions were drawn from this experiment.
    38 (iii) (B)
    Justify the statement : “It is possible that a trait is inherited but may not be expressed.”

  5. Question 5

    How do Organisms Reproduce?. Asked once: 2026 (same type asked 4 times)

    13
    Give reasons for the following : (a) Adrenal gland is known as the stress gland of the body. (b) Prenatal sex determination is banned in India. (c) Vegetative propagation is advantageous in some plants.