It has been claimed that thyroxine is a hormone produced when the body is exposed to cold temperatures. Thyroxine is purported to stimulate an increase in the basal metabolic rate of body cells and also to stimulate an increase in heart rate. Both of these responses result in an increase in body temperature.

a) Design an experiment to test the role of thyroxine in helping the body adjust to cold temperatures. Describe the overall investigation to be done, the variables to be changed, the variables to be kept constant, the subjects to be used, the control and experimental conditions to be used, the type of data collected, and how the data will be collected. Explain how these data can be used to justify the conclusion that thyroxine is involved in adjusting body temperature in response to cold. (9 points)