Multiple choice

A boy has blood group O, his mother has blood group A and his father has blood group B. How many children will have O blood group?

  1. 4 out of 4

  2. 2 out of 4

  3. 1 out of 4

  4. 3 out of 4
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Mother A (genotype I^A I^A or I^A i) × Father B (genotype I^B I^B or I^B i) can produce children with genotypes I^A I^B (AB), I^A i (A), I^B i (B), or ii (O). The Punnett square shows a 1:1:1:1 ratio, giving 25% probability for each blood type including O. The phrasing '1 out of 4' represents this probability per child, not a guarantee across 4 children.

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