The correct answer is: A. Cooling
Evaporation is a cooling process because it removes energy from the liquid. When a liquid evaporates, the molecules at the surface of the liquid have enough energy to escape the attraction of the other molecules and enter the gas phase. This requires energy, which is taken from the liquid. As a result, the liquid cools down.
The amount of energy required to evaporate a liquid is called the latent heat of vaporization. The latent heat of vaporization is a large amount of energy, which is why evaporation can cool things down so effectively.
For example, when you sweat, the water on your skin evaporates and takes heat away from your body, which helps you to cool down.
Option B is incorrect because evaporation is a cooling process, not a heating process.
Option C is incorrect because evaporation is always a cooling process, regardless of the temperature.
Option D is incorrect because evaporation is not both a cooling and a heating process. It is only a cooling process.