The sympathetic nervous system and parasympathetic nervous system work together to maintain a stable a. breathing pattern b. environment c. external state d. internal state

The sympathetic and the parasympathetic nervous systems work together to maintain in a balanced state of homeostasis. The sympathetic takes care of the arousal and the parasympathetic handles the calming.

D. internal state is  correct because i just took the test. 

Less force and energy was applied

That would be kinetic energy