Blood typing is based on the presence of proteins known as antigens/antibodies on the outer surface of the red blood cell plasma membrane.
The four primary blood types are:
Blood group A – has A antigens on the red blood cells with anti-B antibodies in the plasma
Blood group B – has B antigens with anti-A antibodies in the plasma
Blood group O – has no antigens, but both anti-A and anti-B antibodies in the plasma
Blood group AB – has both A and B antigens, but no antibodies
learn more about Blood typing here: https://brainly.com/question/13496262
#SPJ4