Answer:
black is dominant, white is recessive, because both alleles are present but only black physically shows up.
Answer:
Suppose that a mouse with black fur has both an allele for black fur and an allele for white fur (Bb). Based on this information, you can conclude that the dominant allele must be for black fur and the recessive allele must be for white fur.
Explanation:
I know you already have the answer, but I thought I'd help as well.