Which is the primary means of temperature regulation as evaporation becomes dominant?

• A. Radiation
• B. Evaporation
• C. Conduction
• D. Convection

Answer: (B)

When sweating becomes the main way the body sheds heat, it relies on evaporative cooling. As sweat on the skin changes from liquid to vapor, it absorbs a large amount of heat from the body—this latent heat of vaporization—so heat is removed without the skin having to get much hotter than the surrounding air. This makes evaporation an especially powerful cooling mechanism in hot conditions, provided there’s enough air movement to carry the vapor away. Other modes of heat transfer—radiation, conduction, and convection—also occur, but their contribution is limited by environmental factors like clothing, surface temperatures, and humidity. Evaporation dominates because it can remove more heat per unit mass of water than the other methods, making it the primary means of temperature regulation when sweating is active.