Blood type represent contributions from both parents. A total of 36 human blood group systems and 346 antigens are now recognized by the International Society of Blood Transfusion (ISBT). The two most important ones are ABO and the Rh blood group systems; they determine someone's blood type (A, B, AB and O, with +, − or null denoting RhD status) for suitability in blood transfusion. A complete blood type would describe a full set of 30 substances on the surface of red blood cells, and an individual's blood type is one of many possible combinations of blood-group antigens. Across the 36 blood
Blood ritual The Aztecs believed the gods would provide plentiful crops and healthy long lives as long as blood was ritually given (Pendragon 2). If blood was not sacrificed to the gods, the humans believed they would be punished and endure excessive pain “more violent than any man could ever do” (Pendragon 3). Some Indians practice a political ritual voluntarily where the people donate blood as a way to remember politicians who have died (Copeman 126). The blood donation is literally a donation to people who need transfusions (Copeman 132). The participants donate at donation camps during the birthday or the anniversary