Final answer:
The parasympathetic division of the ANS is responsible for reducing energy expenditure and maintaining the body's normal functions, often described by the term 'rest and digest'.
Step-by-step explanation:
The division of the autonomic nervous system (ANS) that is associated with reduced energy expenditure and normal body maintenance is the parasympathetic division. This division is responsible for conserving energy and is often referred to by the phase 'rest and digest.' It works to return the body to a state of homeostasis after stress or emergency situations by slowing down the heart rate, narrowing air passages, reducing blood flow to the skeletal muscles, and stimulating the digestive system.