What is the probability that an individual heterozygous for a cleft chin (Cc) and an individual homozygous for a chin without a cleft (cc) will produce offspring that are homozygous recessive for a chin without a cleft (cc)?

1/2

Here the parental genotype are : Cc and cc The genes are therefore : C c c c Hence, if you draw a punnet's square, it would appear like this

C | c

c|Cc cc c|Cc cc

Hence it stands that Cc : cc =2:2 Thus the probability is 1/2