Question

Mountainous regions were the most ideal places for the development of early civilizations, due mostly to the availability of rich soil for farming

Answer 1

Seems very unlikely. First of all, rich soil is usually generated by erosion and previous plant growth, so as a rule it is maximized in river valleys and along coasts. Mountain regions is where erosion takes soil away, and, because of their harsher climates, where plants grow more slowly and less abundantly.

And, in fact, we see all the centers of ancient civilization developing first in river valleys (Mesopotamia, Egypt) or along coasts (Greece, Rome).