Thermoregulation via heat loss mechanisms

Steps:

• Period 1 shows body temperature decrease from reduced air temperature, enhancing convective and conductive heat loss.
• Exercise during period 1 adds metabolic heat but in cool air results in net cooling if intensity is low.
• Period 2 shows continued or further decrease from increased sweating, promoting evaporative heat loss.
• Option C matches both periods' cooling changes through environmental and physiological cooling.

Why C is correct:

• Reduced air temperature lowers body temperature by increasing heat loss to surroundings; increased sweating lowers it via evaporation, per thermoregulation principles maintaining homeostasis around 37°C.

Why the others are wrong:

• A: Increased air temperature in period 2 would raise body temperature through greater heat gain, not cooling.
• B: Increased shivering in period 2 generates metabolic heat to raise body temperature against cold.
• D: Vigorous exercise and shivering both produce internal heat, elevating body temperature.

Final answer: C