Final answer:
Blood type is determined by the presence or absence of specific antigens on red blood cells, which are classified under the ABO and Rhesus (Rh) systems.
Step-by-step explanation:
Blood type is a genetic characteristic associated with the presence or absence of certain molecules, known as antigens, on the surface of red blood cells. The most commonly recognized blood types are classified in the ABO and Rhesus (Rh) systems. In the ABO system, blood types are determined as type A, B, AB, or O, which describe the specific antigens present on the individual's red blood cells. Additionally, the Rh factor indicates the presence (positive) or absence (negative) of the Rh antigen. Thus, a person's blood type could be A positive if they have type A antigens and the Rh antigen, or A negative if they have type A antigens without the Rh antigen.
Blood type is a genetic characteristic associated with the presence or absence of certain molecules, called antigens, on the surface of red blood cells. The most commonly known blood types are the ABO and Rhesus blood types.