Answer: The presence of the polygenic trait masks the other possible alleles involved. There are only two possible phenotypes for the trait. The graphing of the possible phenotypes results in a bell curve. Usually, traits are polygenic when there is wide variation in the trait. For example, humans can be many different sizes. Height is a polygenic trait, controlled by at least three genes with six alleles. If you are dominant for all of the alleles for height, then you will be very tall.
Step-by-step explanation: