How did both mountains and high plateaus influence the rise and growth of empires in mainland southeast Asia?

Mountains and high plateaus in mainland Southeast Asia served as natural barriers that shaped the political and cultural landscape of the region. These geographical features often isolated communities, leading to the development of distinct cultures and languages, which in turn influenced the formation of smaller kingdoms and empires. However, they also created strategic advantages for empires that could navigate or control these terrains, facilitating trade routes and military campaigns. Ultimately, the interplay between these natural formations and human activity contributed to both the rise and expansion of influential empires like the Khmer and the Dai Viet.