What graph!? If u want me to answer that u have to include a graph sooooo ya
I think genetic variation, but i'm not completely sure
Blood groups are inherited from both parents. The ABO blood type is controlled by a single gene (the ABO gene) with three types of alleles inferred from classical genetics: i, IA, and IB. The I designation stands for isoagglutinogen, another term for antigen.
Counter current involves blood in the capillaries flowing in the opposite direction to the flow of water flowing over them. Gases diffuse faster from one area to another when the concentration difference between the two areas is at its greatest, as compared to when the concentration difference is low.
