What is the probability of having children with 'O' blood group, where both mother and father are heterozygous for 'A' and 'B' blood group, respectively ?

(A) \(25 \%\)
The genotype of the mother, who is heterozygous for 'A' blood group, is \(I^A i\).
The genotype of the father, who is heterozygous for 'B' blood group, is \(I^A i\).
A cross between the mother and father ( \(I^A i \times I^B i\) ) produces the following possible genotypes in the offspring:
\(I^A I^B\) (AB blood group)
\(I^A i\) (A blood group)
\(I^B i\) (B blood group)
\(i i\) (O blood group)
Out of the four possible combinations, only one results in the 'O' blood group \(ii\).
he probability of having a child with 'O' blood group is \(\frac{1}{4}\).
In percentage, this is \(\frac{1}{4} \times 100 \%=25 \%\)