How could forensic scientists use isotopic analysis? ?

Isotopic analysis would refer to looking at isotopes obviously. Forensic scientists would primarily look at the carbon present. By looking at how much carbon is present in proportion to the amount of carbon isotope present, they can determine how old something is (called Carbon Dating). In this case, they'd be able to tell how long a dead body would have been decaying for as an example

Ais the correct answer

Yes it would be a physical change.