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Variation and its value for survival

This type of question, asked 4 times: 2022, 2023, 2025, 2026. All 5 questions below, oldest first.

Try each one first, then open its answer.

  1. Question 1

    2022

    5 (a)
    What is variation ? List two main reasons that may lead to variation in a population.

  2. Question 2

    2023

    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) : Human populations show a great deal of variations in traits. Reason (R) : All variations in a species have equal chances of surviving in the environment in which they live.

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  3. Question 3 (case study, 4 parts)

    2023

    The most obvious outcome of the reproductive process is the generation of individuals of similar design, but in sexual reproduction they may not be exactly alike. The resemblances as well as differences are marked. The rules of heredity determine the process by which traits and characteristics are reliably inherited. Many experiments have been done to study the rules of inheritance.
    38 (i)
    Why an offspring of human being is not a true copy of his parents in sexual reproduction ?
    38 (ii)
    While performing experiments on inheritance in plants, what is the difference between F1\mathrm{F_1} and F2\mathrm{F_2} generation ?
    38 (iii) (A)
    Why do we say that variations are useful for the survival of a species over time ?
    38 (iii) (B)
    Study Mendel’s cross between two plants with a pair of contrasting characters. RRYY (Round Yellow) ×\times rryy (Wrinkled Green) He observed 4 types of combinations in F2\mathrm{F_2} generation. Which of these were new combinations ? Why do new features which are not present in the parents, appear in F2\mathrm{F_2} generation ?

  4. Question 4

    2025

    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.

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  5. Question 5

    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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