Answer:
The ability to produce sweat to cool their bodies.
Step-by-step explanation:
Evolution may be defined as the change in the the characteristics of the species with respect to time. The process of the natural selection plays an important role in evolution.
As the humans are living in hot and dry areas, this allow the change in their physiology and genes that help them to survive according to the environment. The humans produce more sweat. They have well developed sweat glands. These glands help in the production of sweat that ultimately causes cooling in their body.