Solutions For An Introduction to Genetic Analysis Chapter 3 Problem 30P

b) By observing cross 1, female parent is a normal and male parent is the bent type. Males get X chromosome from their mother, so in case 1, all male progeny are normal but female progeny are affected due to the male parent (bent tail).

Male parent passes his one X-chromosome to the daughters, so we can say that this trait is a sex-linked and specifically X-linked trait. Whenever the mother has a bent tail, the male children also have bent tails.