Which system is activated during a 'fight or flight' response?

The sympathetic nervous system is activated during the 'fight or flight' response, which prepares the body to react to perceived threats or danger. This physiological response involves a variety of changes designed to enhance survival, such as increased heart rate, improved blood flow to muscles, and the release of adrenaline. These changes enable a person to either confront the threat (fight) or escape from it (flight).

In contrast, the parasympathetic nervous system is responsible for promoting a state of calm and relaxation following stress, slowing down the heart rate and stimulating digestion. The central nervous system, which includes the brain and spinal cord, processes information but does not directly initiate the fight or flight response. The somatic nervous system controls voluntary movements of skeletal muscles and is not primarily involved in the autonomic responses triggered by stress. Thus, the role of the sympathetic nervous system in activating the body's rapid response to danger clearly identifies it as the correct answer.