Final answer:
The probability of Betty and Ben's offspring being heterozygous cannot be determined without knowing Ben's genotype. It would be 100% if Ben is homozygous recessive (rr) and 50% if he is heterozygous (Rr). In another example involving red and white eye color, there is a 50% probability of offspring being heterozygous if one parent is heterozygous and the other homozygous recessive.
Step-by-step explanation:
The probability of Betty and Ben's offspring being heterozygous depends on Ben's genotype. If Ben is homozygous recessive, all offspring will be heterozygous.
In genetics, when a family is said to be purebred for a specific trait, it usually means they are homozygous for the dominant allele. Assuming 'round head' is the dominant trait (R), Betty's genotype could be represented as RR. Ben has a 'pointy head,' which suggests he has the recessive trait, so his genotype could be rr if he is homozygous recessive, leading to 100% of their offspring being heterozygous (Rr). If Ben is heterozygous (Rr), there would be a 50% chance of their offspring being heterozygous (Rr) and a 50% chance of being homozygous dominant (RR). To fully determine the probability, we would need to know Ben's exact genotype.
In relation to the scenario about red eye color in offspring, if the cross involves a white-eyed male (with genotype bb) and a heterozygous red-eyed female (Bb), the ratio of offspring would be 1:1, meaning half of the offspring would have red eyes and half would have white eyes. This results in a 50% probability of the offspring being heterozygous for the red eye color.