Human activity contributes to the extinction of species. which is not a human activity that contributes to the extinction of a species?
a. introducing a nonnative species
b. hunting
c. fungal disease
d. cutting down forests

Asquirrel population lives in an area. over many years, a river in that area grows wider and stronger, eventually forming a canyon. the squirrel populations on the two sides of the canyon can no longer mate with each other and ultimately form distinct species. this is an example of