
ABO blood group system, the classification of human blood based on the inherited properties of red blood cells (erythrocytes) as determined by the presence or absence of the antigens A and B, which are carried on the surface of the red cells. Persons may thus have type A, type B, type O, or type AB blood.
https://youtu.be/2UxZ8MT1fAE
https://www.rhesusnegative.net/staynegative/how-to-find-blood-type-frequencies-using-hardy-weinberg-equation/
Thanks to Mike at: https://www.rhesusnegative.net