In cows black (B) is dominant to brown (b). If a brown purebred cow was mated with a black purebred cow what would the resulting offspring be in Box "2"……. {3...80%}

All black offsprings (Bb)

Explanation:

This question involves a single gene coding for skin color in cow. The allele for black color (B) is dominant over the allele for brown color (b). This means that allele 'B' will always mask the phenotypic expression of allele 'b' in a heterozygous state.

Based on the question, a brown purebred cow mates with a black purebred cow. A purebred cow means a cow that is homozygous (same allele) for a particular trait and produces only one type of gamete. Hence, a purebred brown cow will have genotype: bb while a purebred black cow will have genotype: BB.

If BB and bb are involved in a cross, each parent cow will produce gametes with genotypes B and b respectively. Using these gametes in a punnet square (see attached image), all offsprings of this cross will possess a genotype: Bb, which will be phenotypically black because the black allele (B) will exhibit its dominance.