Which are the four mechanisms of heat transfer used by the body?

• A. Osmosis, diffusion, convection, evaporation
• B. Radiation, conduction, convection, evaporation
• C. Radiation, conduction, evaporation, diffusion
• D. Conduction, convection, evaporation, diffusion

Answer: (B)

Heat transfer in the body occurs mainly through four mechanisms: radiation, conduction, convection, and evaporation. Radiation is energy exchanged as infrared heat with surrounding objects without contact, so you can gain or lose heat from nearby surfaces. Conduction happens when the body is in direct contact with a warmer or cooler object, transferring heat through molecular interactions at the interface. Convection involves moving air or blood carrying heat away from or toward the body; natural convection relies on buoyancy, while forced convection uses air currents or circulating blood. Evaporation is heat loss as sweat or moisture on the skin or in the respiratory tract evaporates, which requires latent heat and cools the body. Other processes like osmosis or diffusion involve movement of water or solutes due to concentration gradients and do not function as primary routes for heat transfer in the body.