16 7 When scientists visit Antarctica, they need appropriate clothing to help with thermoregulation. www.aa.com (a) An investigation was carried out to study thermoregulation in humans. A woman was wrapped in blankets and her feet were put in hot water for 30 minutes. During this time, the temperature of the skin at the end of one of her fingertips was recorded. The graph shows the results of this investigation. 35 33 31 29 27 25 23 21 19 17 0 0 5 10 15 20 25 30 Time / minutes Fingertip temperature / °C 17 Turn over (i) Explain why there was no change in fingertip temperature between 0 and 3 minutes. 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(ii) Calculate the greatest rate of increase in fingertip temperature. (2) Answer ............................................................................................. 18 (iii) Explain the role of the nervous system in bringing about the increase in temperature of the fingertip as shown in this investigation. 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(b) Sweating is a thermoregulatory mechanism. A student stated that loss of heat when sweating is related to the dipole nature of water molecules. Justify this statement. 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(Total for Question 7 = 12 marks)