Respuesta :
Answer;
Blood group B
Explanation;
- Mary has blood type A, and the son has blood type AB.
- An individual with blood type A must have either one or two copies of A allele, that is either AA, or AO genotype.
- Similarly with blood group B, the genotype may be either be BB or BO.
- Therefore, since Mary has blood group A, and the son Bill has blood group AB, it means that the father would have blood group B. This is because Mary will pass A allele to their son and the father will pass B allele to the son.