If the allele combinations of a Punnett Square for hair color are BB and bb, what is the probability of offspring having red hair?

In a Punnett Square where the parental allele combinations are BB and bb, the resulting allele combinations for the offspring can only be Bb in the F1 generation. This is because the offspring receive one allele from each parent; in this case, the B allele from the BB parent and the b allele from the bb parent.

To determine the hair color based on the alleles, it is important to know the dominance relationships: typically, uppercase letters (B) represent dominant traits and lowercase letters (b) represent recessive traits. Assuming brown hair (B) is dominant over red hair (b), all offspring with the Bb genotype will express the dominant trait, which is brown hair.

Since there are no offspring that can inherit the bb genotype (which would express the recessive trait of red hair), the probability of producing an offspring with red hair in this scenario is zero in four. Thus, the correct answer reflects that there are no combinations from this specific cross that would lead to red-haired offspring.