Question

What blood types are possible for a child whose parents both have AB bloodtype?I. AII. BIll. ABIV. OA. Only IB. Ill and IVC. I and IlD. I, Il, and Ill

Answer 1

They are asking us the possible blood types for a child of parents with AB blood type.

This means that both parents have one allele for antigen A (Iᵃ) and one allele for antigen B (IᵃIᵇ):

Mother: IᵃIᵇ

Father: IᵃIᵇ

Just from that, the child cannot be type O, because there is no allele for not having any antigen (i).

Let's look at the Punnet's square:

As we can see, the child of this couple could have blood type A, B, or AB.

This means the right answer is D. I, Il, and Ill