What factor determines the climate in bolivia's different regions?

The main factor that determines the climate in Bolivia is the elevation. In the Andes there is the altiplano which is a high plane which is basically a desert due to being on the leeward side of the prevailing wind. In the higher Andes, the altitudes up to 5000m or more there are alpine glaciers and snow due to the cold temperatures due to the high elevation. On the other hand, in the eastern tropical rainforests the elevation is much lower and precipitation falls as rain which nourishes the tropical plants. 

Answer collision and mountain formation;