The conversation between human and AI assistant.
Why do we have different blood group?
Can you tell me why we have different blood groups?
Sure! Blood groups are determined by the presence or absence of certain proteins, called antigens, on the surface of red blood cells. The ABO blood group system is based on two antigens — A and B. People who have antigen A on the surface of their red blood cells have blood group A, and those with antigen B have blood group B. People who have both antigens have blood group AB, while those who have neither antigen have blood group O.