Malcolm is studying alone in his room late at night when he hears a loud noise downstairs. his heartbeat increases significantly and his breathing becomes shallow. he wonders if a burglar has entered the house and decides to investigate. when he gets downstairs he discovers his cat has knocked over a plant stand. his body begins to relax and return to normal. which part of his nervous system is responsible for returning malcolm to a normal state?
a. spinal cord
b. somatic nervous system
c. sympathetic nervous system
d. parasympathetic nervous system
e. the corpus callosum