Answer: The possible blood type for their baby is blood type B
Explanation: The dad is homozygous for blood type B allele, this means that he has two alleles of blood type B, therefore his genotype for the blood type is BB. The mom has blood type O, blood type O is recessive therefore the genotype of the mom is OO.
A cross between BB and OO will produce BO, BO, BO, and BO. All the offsprings will have NO genotype and this means that all of them will have blood type B.
See the attached punnet square for further information
