A postal worker's skin temperature stays at 34 ∘C34\ ^\circ\mathrm{C}34 ∘C while the air temperature in the sorting hall rises from 27 ∘C27\ ^\circ\mathrm{C}27 ∘C to 39 ∘C39\ ^\circ\mathrm{C}39 ∘C. The worker's sweat continues to evaporate.
Which statement describes the energy transfers at the worker's skin as the air warms?
Heat is transferred from the skin to the air at first, then from the air to the skin; sweat evaporation transfers energy from the skin only while the air is cooler than the skin.
Heat is transferred from the skin to the air the whole time; sweat evaporation transfers energy from the skin only while the air is cooler than the skin.
Heat is transferred from the skin to the air the whole time; sweat evaporation transfers energy from the skin the whole time.
Heat is transferred from the skin to the air at first, then from the air to the skin; sweat evaporation transfers energy from the skin the whole time.
78 exam-style questions on Edexcel GCSE Biology 7.3 Homeostasis and thermoregulation, covering 7.3.1 Importance of a constant internal environment, 7.3.2 Importance of homeostasis, 7.3.3a Thermoregulation via the skin and hypothalamus, and 7.3.3b Vasoconstriction and vasodilation in thermoregulation. Each one has a worked solution and a mark scheme showing where the marks go.