So now that we discuss the four different types of blood types, blood groups, let's discuss the process of blood transfusion. So it is actually possible to transfer blood from one individual to a different individual. However, one must keep in mind that certain blood types cannot be mixed and that's because if they are mixed they will agglutinate. And what that means is antibodies will combine with their complementary antigens and they will basically clump together and the blood will be rejected during that transfusion process. So this is because people carry antibodies for antigens they don't have. And so mixing red blood cells that have particular antigens with complementary antibodies will cause them to stick together causing the process of Agglutination.