ABO blood groups are based on the inheritance of which two antigens?

ABO blood groups are determined by the presence or absence of specific antigens located on the surface of red blood cells. The two key antigens involved in this system are type A and type B antigens. Individuals inherit these antigens from their parents, leading to four possible blood types: A, B, AB, and O.

In type A blood, the A antigen is present, while type B blood has the B antigen. Type AB blood contains both A and B antigens, and type O blood lacks these antigens entirely. The genetic basis for this inheritance involves a single gene that has three alleles: A, B, and O. When a person inherits one of the A alleles and one of the B alleles, they express both antigens and thus fall into the AB blood group. Therefore, the correct answer highlights the presence of the A and B antigens as the determinants of the ABO blood groups.