(a)[2]
Explain what the term sex linkage means.
(b)[5]
With appropriate symbols, finish the genetic diagram below. Key to symbols: recessive allele; dominant allele. Parental phenotypes: male with CI $\times$ normal female. Fill in the parental genotypes, gametes, offspring genotypes and offspring phenotypes.
(c)[1]
A woman who is heterozygous for CI is pregnant with a man who has a normal iris. State the probability that their child will have CI.