Why do you think the chavin and inca civilizations were confined to mountainous areas?

The correct answer to this open question is the following.

The Chavin and Inca civilizations were confined to mountainous areas because that was the best way to be isolated in order to avoid ant invasion from outer tribes.

For instance, the impressive city of Machu Picchu was built at the top of the Andean Mountains in Perú. Its impressive architecture, the heavy pieces of rocks used and the way they prepared the land to grow crops in such difficult conditions, could be even harder if the Incas had to fight foreign invaders. So yes, being isolated in this way represented a major advantage for them

hey i did something like that before, what is the quesiton?

explanati“there were many such dangers, in which the odds were all against them. their children were not as well as they had been at home; but how could they know that there was no sewer to their house, and that the drainage of fifteen years was in a cesspool under it? how could they know that the pale-blue milk that they bought around the corner was watered, and doctored with formaldehyde besides? when the children were not well at home, teta elzbieta would gather herbs and cure them; now she was obliged to go to the drugstore and buy extracts–and how was she to know that they were all adulterated? how could they find out that their tea and coffee, their sugar and flour, had been doctored; that their canned peas had been colored with copper salts, and their fruit jams with aniline dyes? and even if they had known it, what good would it have done them, since there was no place within miles of them where any other sort was to be had? the bitter winter was coming, and they had to save money to get more clothing and bedding; but it would not matter in the least how much they saved, they could not get anything to keep them warm. all the clothing that was to be had in the stores was made of cotton and shoddy, which is made by tearing old clothes to pieces and weaving the fiber again. if they paid higher prices, they might get frills and fanciness, or be cheated; but genuine quality they could not obtain for love nor moneyon: