Answer: A. Sweat released onto the skin can evaporate, removing heat from the body and helping lower its temperature.

B: Vasodilation increases heat transfer to the skin but does not provide the water for evaporation.
C: Shivering contractions generate heat rather than directly increasing evaporative heat loss.
D: Hair erection helps retain an insulating layer of air, reducing heat loss.

Remember: sweating promotes evaporative cooling, whereas vasodilation promotes heat transfer to the skin.