I think the answer to this is the kidneys
The odds are astronomical for a father with AB(IV) to have an O(I) child. The only possible way for this phenomenon to occur is if there was a nondisjunction in the ovogenesis for the 9th chromosome and the father also had a nondisjunction for the same chromosome(A sperm cell with no 9th chromosome fertilized an ovum with two 9 chromosomes).
A person with AB cannot donate to a person with O because the receiver has antibodies(alpha and beta) that bind to the antigens on the AB blood cells, causing death.
Learning about the different body parts will help us better understand human life and health because it can make us care about others instead of just are selves and encourage us to do something about the health difficulties in life.
