O-LevelBiologyGenetics & Variation5090/11 · May/June 2020 · Q391 Mark

The inheritance of the ABO blood groups in humans is controlled by three alleles (Iᴬ, Iᴮ and I⁰), only two of which can be present in one individual. What are the possible blood groups of children born to a homozygous group A woman and a heterozygous group B man?

AAB and B only

BAB and A only

CA, B and AB only

DA, B, AB and O

✓ Correct answer

B: AB and A only

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Topic: Genetics & Variation, O-Level Biology (syllabus 5090). Multiple choice, 1 mark.
Source: O-Level Biology, May/June 2020 Paper 1 Variant 1, question 39.

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