What is the phenotype of a homozygous brown mouse being crossed with heterozygous brown mouse?

In a cross between a homozygous brown mouse (BB) and a heterozygous brown mouse (Bb), all offspring will display the brown phenotype. This occurs because both parental genotypes carry the brown allele (B), and the presence of at least one brown allele results in a brown fur color. The genotypic ratio of the offspring will be 50% BB and 50% Bb, but all will exhibit the brown phenotype.