Sweating does not cool the body unless evaporation takes place (need dry air). Which option best states this concept?

• A. Sweating cools the body regardless of evaporation
• B. Sweating does not cool the body unless evaporation takes place (need dry air)
• C. Evaporation is not important for cooling
• D. Cooling occurs primarily by conduction

Answer: (B)

Sweating cools the body through evaporation. When sweat on the skin turns into vapor, it absorbs a large amount of heat from the body (latent heat of vaporization), which lowers skin and internal temperature. If the surrounding air is humid and cannot absorb more moisture, evaporation slows or stops, so sweating no longer provides cooling effectively. Therefore, the statement that sweating does not cool the body unless evaporation takes place—and that dry air is needed for that evaporation—is the best way to express this concept. The idea that sweating cools regardless of evaporation isn’t accurate, and evaporation is the essential mechanism—not conduction, which plays a much smaller role in this context.