blood-types

Blood types are inherited molecular markers on red blood cells. The ABO polymorphism has been kept alive in primates for at least 20 million years, and infections such as malaria, cholera, and norovirus are the leading explanation for why.

Your body contains roughly 5 liters of blood, and every drop of it completes a full circuit through the heart and lungs in about 60 seconds. Blood is not a simple liquid — it is a suspension of at least four distinct components performing oxygen transport, immune defense, wound sealing, and chemical delivery simultaneously. Here is how it all works.

ABO and Rh blood groups explained — antigens, antibodies, inheritance, transfusion compatibility, and whether blood type can be changed.