The possibilities of combinations from her parent’s gametes would be BB, inheriting a dominant trait from both parents and would occur 25% of the time, Bb, inheriting either a dominant from the maternal side OR the paternal side but not both, and because there are two ways to obtain this combination of gametes, the probability is twice that of a combination that could only occur in one way (like having BB, which was 25%, so Bb must be 50%), and lastly, bb, inheriting a recessive trait from both parents and would only occur the remaining 25% of the time. This is the group that Jessica calls into.
