Which term describes the chromosomal adnormality of having three copies of a single chromosomes?

Trisomy is correct!

A trisomy occurs when a diploid cell has three copies of a particular chromosome instead of two.

i'm gonna put a couple so you can chose from

explanation:

if you know the fur color of the offspring mice, you can use the ratios to identify the genotypes of the parents.

if either parent mouse passes a dominant allele, the offspring will have black fur.

if the parental mice has two different fur color (i.e white and black) , the color of the offspring's fur would be either black, white, or the combination of both (grey)

hope this : )

i don't know, but does anyone wanna be friends? i'm doing my homework at 1: 49 in the morning : /