WAEC Biology 2024 Papers

Concept:A child with blood group $O$ must inherit the $i$ allele from both parents.Explanation:Mother has blood group $A$, so her possible genotypes are $\mathrm{I}^A \mathrm{I}^A$ or $\mathrm{I}^A i$.Since the child has blood group $O$, the child's genotype is $ii$.Therefore, the child must receive an $i$ allele from the mother.So the mother must be heterozygous, $\mathrm{I}^A i$.The father must also supply an $i$ allele for the child to be $O$.A man with blood group $AB$ has genotype $\mathrm{I}^A \mathrm{I}^B$ and cannot produce the $i$ allele.Hence, blood group $AB$ cannot belong to the father.Answer:Option C: AB.