Option 1: Presence of water on the skin is cooling. This option is incorrect. While it is true that water on the skin can provide a temporary cooling sensation, perspiration itself does not cool the body solely by its presence on the skin.

Option 2: Evaporation requires latent heat. This option is correct. When sweat evaporates from the skin`s surface, it absorbs heat energy from the body, which cools the body down. This is because the process of evaporation requires energy, known as latent heat, to transform liquid water into water vapor. This energy is extracted from the body, resulting in a cooling effect.

Option 3: Water has a high specific heat. This option is irrelevant to the cooling effect of perspiration. While water does indeed have a high specific heat, meaning it takes a relatively large amount of energy to heat water, it does not directly contribute to the cooling effect of perspiration.

Option 4: Water is a poor conductor of heat. This option is also irrelevant to the cooling effect of perspiration. Although water is a poor conductor of heat compared to metals, the cooling effect of perspiration is primarily due to the evaporation process, not the conduction of heat.

Therefore, the correct answer is option 2,