The fight-or-flight response is stimulated by the _____.

• A. Parasympathetic nervous system
• B. Central nervous system
• C. Somatic nervous system
• D. Sympathetic nervous system

Answer: (D)

The fight-or-flight response is driven by the sympathetic branch of the autonomic nervous system. When a threat is perceived, this branch kicks in to ready the body for action—heart rate and blood pressure rise, airways open wider to increase oxygen, the liver releases glucose for quick energy, pupils dilate, and nonessential functions like digestion are downregulated to conserve energy. The parasympathetic division, by contrast, helps the body relax and recover after the threat passes. The central nervous system is the brain and spinal cord that process information, not the specific trigger for this rapid arousal, and the somatic nervous system controls voluntary muscles, not automatic stress responses. So, the fight-or-flight response is stimulated by the sympathetic nervous system.