Answer:
Yes, it is possible.
Explanation:
Bob could either be h.o.m.ozygous (BB) for brown hair or h.e.terozygous (Bb) for brown hair. If Bob is h.e.t.erozygous for brown hair, this means he has a blonde hair allele. For a child to be blonde, the child needs one blonde allele from each parent and this is possible if Bob has a blonde hair allele. However, it is not possible if Bob is h.o.m.ozygous for brown hair.
In the image, there is a punnet square showing the possible genotypes of the children if Bob is h.e.t.erozygous for brown hair.
