Scientists investigate whether hotter surroundings increase blood flow through capillaries near the skin surface. Each volunteer sits in a cool room for the first trial and walks in a hot room for the second trial. Mean surface blood flow is greater in the second trial.
Which revised procedure would provide the strongest test of the effect of room temperature?
use seated volunteers in the cool room and different walking volunteers in the hot room
have each volunteer walk in the cool room and sit in the hot room, then compare mean surface blood flow
have each volunteer sit in both rooms and compare mean surface blood flow
have each volunteer walk faster in the hot room and compare maximum surface blood flow
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.