If the offspring of a cross between a brown mouse (bb) and a black mouse (BB) ar...

This Biology question is asking about the genotypes that would result if the offspring of a cross between a brown mouse (bb) and a black mouse (BB) are allowed to interbreed. The question wants to know how many different genotypes would be produced.

When the offspring of the cross between brown and black mice are allowed to interbreed, there are four possible genotypes that could result. The possible genotypes are BB, Bb, bb, and Bb. BB represents a black mouse, Bb represents a mouse with a heterozygous genotype, bb represents a brown mouse, and Bb represents another mouse with a heterozygous genotype.

It is important to note that the original parents of the first cross between the brown and black mouse have the genotypes bb and BB. The first generation of offspring would all have the Bb genotype (heterozygous), which is a mix of the dominant and recessive alleles.

When the second generation of offspring is produced from the first generation of Bb mice, there are four possible genotypes that could result, which are BB, Bb, bb, and Bb. Therefore, the correct answer to this question is option C, which is 4.

In summary, when the offspring of a cross between a brown mouse and a black mouse are allowed to interbreed, four different genotypes could result, which are BB, Bb, bb, and Bb.