Mutations may change the structure of a chromosome or just change a single nucleotide.
Mutations in genes on the y chromosome have been implicated in male genetic infertility.
Changes in the structure of the y chromosome are implicated in male infertility.
What does changes in the structure of the Y chromosome do?

(a) reproduce
(b) Male infertility
(c) harm them
(d) bending light rays
(e) It expands
(f) allow growth
(g) Plant growth is reduced
(h) Damages them