5.3a Dynamic equilibrium results from detection of and response to stimuli. Organisms
detect and respond to change in a variety of ways both at the cellular level and at the
organismal level.
5.3b Feedback mechanisms have evolved that maintain homeostasis. Examples include
the changes in heart rate or respiratory rate in response to increased activity in muscle
cells, the maintenance of blood sugar levels by insulin from the pancreas, and the
changes in openings in the leaves of plants by guard cells to regulate water loss and gas
exchange.