Mountains also have an unmatched power to drive human evolution. Starting tens of thousands of years ago, people moved to high altitudes, and there they experienced natural selection that has reworked their biology. In Tibet, for example, people have broader arteries and capillaries. In the Andes, they can dissolve more oxygen into their blood. These different traits of people who live in high altitudes illustrate_?

The correct answer is adaptive evolution.

Explanation:

The evolutionary modifications that arise in order to get adapt to the specific environment are termed as adaptive evolution. Such modifications enhance the chances of reproduction and survival by getting used against the specific challenge imposed by the surroundings. The concept of adaptive evolution arises due to the phenomenon of natural selection.  

It is due to adaptive evolution that the emergence of different species takes place on the basis of the specific environments on which the species thrive. Like the populations of human beings living in higher altitudes possess different characteristics than the humans living in terrestrial habitats. This changes most likely results due to adaptive evolution.  

b brown mice / white sand dunes