It may be c, if not you can punch me in the face.
Answer:
The fundamental structure of a chromosome is subject to mutation, which will most likely occur during crossing over at meiosis.
Explanation:
I cant help you with that
It is the identity of the genes of your chromosomes that is your genetics that may not be physical, as compared to a phenotype which is a physical trait.
It allows the scientist to determine the age of the rock it is in