Answer :
Final answer:
The main contributors to heat loss during exercise at varying temperatures are radiation and convection at lower temperatures, and evaporation increasingly becomes more dominant at higher temperatures. The correct option identifying these mechanisms is b) Convection and radiation.
Explanation:
The major contributors to heat loss during exercise at different temperatures such as 10, 20, and 30 degrees Celsius are dependent on various mechanisms of heat transfer. The body loses heat through radiation, convection, conduction, and evaporation. At lower temperatures, such as 10 degrees, radiation and convection primarily drive heat loss, as the body emits heat to the cooler environment and cool air moves across the body's surface. As the temperature increases to 20 and 30 degrees, evaporation increasingly becomes a more dominant method of heat loss, particularly through the process of perspiration.
While conduction may play a role in heat loss during contact with cooler surfaces, it is less significant than radiation and convection at lower temperatures, and less significant than evaporation at higher temperatures when exercise leads to sweating. Therefore, the correct option that identifies the major contributors of heat loss during exercise across the range of given temperatures is b) Convection and radiation.
