Question

child has the blood group (O), so ti is impossible for his mother to have group
(A)
(B)
(AB)
(O)

Answer 1

If a child has blood group O, it is impossible for his mother to have blood group AB. This is because blood group AB is formed from alleles A and B, and a mother with blood group AB could only pass on an A or B allele to her child, resulting in either blood group A or B, not O.