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JAMB and WAEC Biology questions: Heredity and variation

60 questions with answers and explanations. Tap an option to check yourself.

AllJAMBWAEC
All topicsCell structure and organisation · 56Cellular activities · 56Co-ordination and control · 58Ecology · 71Evolution · 45Excretion · 52Growth · 45Heredity and variation · 60Nutrition · 64Reproduction · 62Respiration · 55Support and movement · 50Transport · 57Variety of organisms · 60

  1. Question 41· Heredity and variation· WAEC

    Crossing two heterozygous tall plants (Tt × Tt) gives a phenotypic ratio of

    Explanation and discussion

  2. Question 42· Heredity and variation· JAMB

    A person who carries the sickle-cell gene but does not suffer from the disease has the genotype

    Explanation and discussion

  3. Question 43· Heredity and variation· WAEC

    The ABO blood groups are an example of

    Explanation and discussion

  4. Question 44· Heredity and variation· WAEC

    A cross between two heterozygous tall pea plants (Tt × Tt) produces offspring in the ratio

    Explanation and discussion

  5. Question 45· Heredity and variation· JAMB

    Haemophilia is more common in men than in women because it is

    Explanation and discussion

  6. Question 46· Heredity and variation· JAMB

    Diagram for this question

    In the cross shown, T (tall) is dominant over t (dwarf). What percentage of the offspring are dwarf?

    Explanation and discussion

  7. Question 47· Heredity and variation· JAMB

    If a heterozygous tall plant (Tt) is crossed with a dwarf plant (tt), the ratio of tall to dwarf offspring is:

    Explanation and discussion

  8. Question 48· Heredity and variation· JAMB

    A scar on the skin is an example of

    Explanation and discussion

  9. Question 49· Heredity and variation· JAMB

    Down's syndrome is caused by

    Explanation and discussion

  10. Question 50· Heredity and variation· JAMB

    In a dihybrid cross between two double heterozygotes (AaBb × AaBb), the expected phenotypic ratio is

    Explanation and discussion

  11. Question 51· Heredity and variation· JAMB

    A mother is a carrier of haemophilia and the father is normal. What is the probability that a son of theirs has haemophilia?

    Explanation and discussion

  12. Question 52· Heredity and variation· WAEC

    A person with sickle cell trait has the genotype

    Explanation and discussion

  13. Question 53· Heredity and variation· WAEC

    The scientist known as the father of genetics is

    Explanation and discussion

  14. Question 54· Heredity and variation· JAMB

    A test cross is used to find out whether an organism showing a dominant trait is

    Explanation and discussion

  15. Question 55· Heredity and variation· JAMB

    Genes are located on

    Explanation and discussion

  16. Question 56· Heredity and variation· WAEC

    Two heterozygous tall pea plants (Tt × Tt) are crossed. What is the phenotypic ratio of the offspring?

    Explanation and discussion

  17. Question 57· Heredity and variation· JAMB

    Which of the following is an example of continuous variation?

    Explanation and discussion

  18. Question 58· Heredity and variation· JAMB

    In peas, round seed (R) is dominant to wrinkled seed (r). What fraction of the offspring of Rr × rr will be wrinkled?

    Explanation and discussion

  19. Question 59· Heredity and variation· JAMB

    An organism with two identical alleles for a trait is

    Explanation and discussion

  20. Question 60· Heredity and variation· WAEC

    Haemophilia is more common in males because it is

    Explanation and discussion

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