9. Classification of blood groups is based on the presence or absence of inherited. 2017

antigens on the surface of red blood cells. The four main blood groups are A, B, AB, and O. Blood group A has A antigens on the surface of red blood cells and anti-B antibodies in the plasma, blood group B has B antigens on the surface of red blood cells and anti-A antibodies in the plasma, blood group AB has both A and B antigens on the surface of red blood cells and no antibodies in the plasma, and blood group O has no antigens on the surface of red blood cells and both anti-A and anti-B antibodies in the plasma.