posted by Bill .
If a breeder wanted to discover whether a black guinea pig was homozygous (BB) or heterozygous (Bb) for coat color, the animal in question could be crossed with an individual with what phenotype?
Whatever bb stands for, that is the one you would use as a mate. If the Black guinea pig was Bb, about half of the offspring would show the b phenotype — whatever that is. If BB, all of the offspring would be black.
You can verify this by using the Punnett square.
I hope this helps. Thanks for asking.