Blood type is based on particular molecules (called antigens) that sit on the surface of red blood cells. People either have A antigens (type A blood), B antigens (type B), both (type AB) or neither (type O) on their red blood cells. When it comes to Rh factor, some people have the antigen (Rh-positive) and some people don't (Rh-negative.) In other words, your blood type identifies which antigens you have from each group.
People are not reptiles. Everything you read on the internet is not true.