Final answer:
The climate in Bolivia's different regions is primarily determined by the elevation above sea level. As elevation increases, temperatures decrease and precipitation patterns vary, which leads to diverse climate zones across the country.
Step-by-step explanation:
The factor that determines the climate in Bolivia's different regions is B) Elevation above sea level. Bolivia is a country with extreme geographical diversity, which includes the Andes Mountains and the Amazon Basin. The variations in elevation lead to distinct climate zones, or altitudinal zonation, as one moves from lowland to highland areas. As elevation increases, temperature typically decreases, which is why higher areas may have snow-capped peaks, while lower areas experience warmer climates.
The highlands, such as the Altiplano region with Lake Titicaca, have colder temperatures due to their elevation. Conversely, the interior on the eastern side of the mountain range has a humid, tropical climate with heavy precipitation, largely because it borders the vast Amazon Basin. The Andes Mountains also influence the distribution of precipitation, with certain areas lying in the rain shadow of these mountains experiencing much less rainfall.
It is these factors that also help to determine the nature of the biomes found in Bolivia, from lush rainforests in the lowlands to arid deserts and alpine tundra in the highlands.