How were the Incan people able to build their empire in such challenging terrain?

Explanation:

The Inca employed a technique called as terrace farming to overcome this challenge. They created terraces by erecting barriers on slopes and filling them with soil. Terraces are a series of broad stairs built into the side of mountains. The hilly topography might have been too difficult for farmers to irrigate, plough, and produce even without terraces.

no, to many things have came in to factor