AP BIOLOGY

Detailed explanation-1: -In most cases, an O parent and an AB parent will have only A or B kids. I added a table at the end of this answer that has all blood type combinations for two parents plus the possible blood types for their children. Exceptions to these rules are extremely rare.

Detailed explanation-2: -If the father’s blood group is O, he has the genotype IOIO or (ii) . The mother has blood type AB, which means that her genotype would be IAIB. The possible combinations of these two groups would result in children having genotypes IAIO or IBIO, which would give them blood groups A or B respectively.

Detailed explanation-3: -Usually, an AB parent and an A parent can only have children who are Type A or Type B. One exception is in certain Asian groups. Some of these folks have a rare version of the ABO blood type gene called cis-AB. People with this gene version have an AB blood type but can easily have an O child.

Detailed explanation-4: -If a woman has AB blood group, they have alleles A and B while her husband has blood group O that means he is homozygous for allele O. Hence, their child would have either blood group A or B. Therefore, the couple has a 50 percent chance of having blood type A.