Final answer:
Epistasis is the phenomenon in which a single gene affects multiple seemingly unrelated characters. Eye color in humans is determined by multiple genes, with at least eight genes contributing to the final eye color.
Step-by-step explanation:
Epistasis is the phenomenon in which a single gene affects a number of seemingly unrelated characters. It occurs when the expression of an allele for one gene masks or modifies the expression of an allele for a different gene.
For example, eye color in humans is determined by multiple genes, with at least eight genes contributing to the final eye color. This is an example of epistasis, where the interaction of multiple genes influences a single trait.