What is the difference between being controlled by multiple alleles and polygenic inheritance?

Question

please help? im confused on this....

Answer 1

Multiple alleles are variants of one gene.  The ABO blood groups are determined by three alleles for the trait, dominant I with either A antigen or B antigen.  Both are dominant to gene i that has neither A or B antigen so it is designated as type O.

Polygenic inheritance involves multiple genes on different chromosomes.  How many dominant and recessive genes you have will determine things such as height, eye color, hair color and skin color.