Researchers compare skin temperature before and after a person takes a substance believed to cause vasodilation. The room is warmer during the second measurement. Skin temperature is higher after the substance is taken.
Which change would most directly help determine whether the substance caused the increase?
keep room temperature constant and compare the substance with a placebo
keep room temperature variable and repeat the measurement more often
keep final skin temperature constant and compare the substance with a placebo
keep the dose variable and measure skin temperature with greater precision
44 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.