As Molly is walking across campus, a car swerves toward her. Her heart races and sweat breaks out as she jumps out of harm's way. This mobilization of energy is due to the action of Molly's __________

A) somatic nervous system.
B) skeletal nervous system.
C) parasympathetic nervous system.
D) sympathetic nervous system.

The sympathetic nervous system is responsible for the body's fight or flight response in times of stress or danger. This response includes the mobilization of energy and increased heart rate and sweating, matching the physiological symptoms experienced by Molly in this situation. The somatic nervous system and skeletal nervous system are involved in voluntary movement and control of skeletal muscles, but not the stress response. The parasympathetic nervous system is responsible for the body's rest and digest response, which is the opposite of the fight or flight response.