How many genes influence a polygenetic trait?

A: one gene

B: more than one gene

C: zero genes, just the environment

D: one gene with multiple alleles

Answer: B: more than one gene

Explanation: A polygenic trait is a trait that is influenced by more than one gene. Every trait is controlled by at least one pair of gene. When a trait is controlled by one gene, it is called a monogenic trait but when a trait is controlled by more than one gene, it is called a polygenic trait. Polygenic traits do not obey mendelian pattern of inheritance and they involve the interaction of multiple genes. Examples of polygenic traits in humans are hair colour, eye colour, skin colour.