Women have sex chromosomes xx, and men have sex chromosomes xy. which of a woman's grandparents could not be the source of any of the genes on either of her x chromosomes?
a) mother's mother
b) father's mother
c) mother's father
d) father's father

D) Father's father. The woman receives an X chromosome from both her parents. Her mother did the same, so it could be either of her mother's parents. The father, however, only receives an X chromosome from his mother, so it cannot be his father's genes.

The answer is d. disruptive

It explains why rocks appear in layers