What evidence could the authors use to support their claim
in the last sentence of this excerpt? Select three options.

Is there any answer choices ?

The correct answer here would be "a"

The correct answer in this question  is option c. people in mountainous areas tend to be more isolated from other populations. this is the reason why their local languages do not spread. farming is their  one way of living among the highlanders.

In english this question is what are all the roots with alternative vowels with this root.