explain why a father with blood group AB cannot donate for a child with blood group O when he marries a woman with blood group O

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.

Displacement

Explanation:Displacement is the change in position of an object. The SI unit for displacement is the meter. Displacement has direction as well as magnitude. Distance traveled is the total length of the path traveled between two positions.