Final answer:
The Andes Mountains, the Himalayas, and the Tibetan Plateau are regions where people often live at higher altitudes. These areas exhibit varied altitudinal zonation and climate types, and indigenous populations have developed unique adaptations to the low-oxygen environment.
Step-by-step explanation:
In considering regions where people often live at higher altitudes, one must look into areas where altitudinal zonation creates a variety of climates and living conditions at different elevations. Among the options provided, A. the Andes Mountains, C. the Himalayas with the Himalayan Mountains, and E. the Tibetan Plateau are notable for high-altitude human settlements.
The Andes Mountains and particularly the regions that are within the tropics showcase varied zones of climate and human activity with different altitudinal zonation, from type A climates at the base to type H highland climates at higher elevations. This zonation influences indigenous people's adaptation to living in a low-oxygen environment, as seen by the higher hemoglobin in their blood. Moreover, the proximity of the Andes to the Pacific Ocean influences the unique adaptations and cultural developments in these high-altitude regions.
The Himalayas are home to the world's highest peak, Mount Everest, and are a key feature of the landscape in countries like Nepal and Tibet. The ecological diversity sustains various rivers and has historically been a center for civilizations. The adaptation of native people, such as Tibetans who compensate for low oxygen levels with increased breathing rates, showcases human variation resulting from the environmental challenge of high altitudes.
The Tibetan Plateau, often referred to as "the Roof of the World" due to its extreme elevation, harbors a sparse population with adaptations suited to the harsh climate that includes hailstorms and a rocky, barren landscape. Its high elevation and type H climate make it one of the most distinctive high-altitude regions in the world.