Some animals shiver as a natural, involuntary response to their environment. shivering generates heat. this is an example of which function?

I believe maintaining homeostasis by regulating body temperature is the answer

You can drink laxative, or  do this exercise when you are sitting in the bathroom on the toilet. to relieve  constipation  fast or in about 1 minute, pinch your nose after your usual exhalation. start holding your breath. but do not mouth breath during this just hold your breath.