4. Give an example of positive feedback in physiology. In your example, how does the controlled variable return from its extremum, after
the positive feedback control system has driven it there?
You might use any example in which the output is driven to an extremum -- bearing down in childbirth, sexual arousal, sneezing, voiding a lumen … In every physiological case I can think of, the positive feedback control ends once an extremum is reached, and a negative feedback controller restores homeostasis.