Which hormone is primarily associated with the fight or flight response in humans?

• A. A hormone that promotes digestion.
• B. A hormone that lowers blood sugar.
• C. A neurotransmitter involved in sleep.
• D. The hormone associated with the fight or flight response in humans.

Answer: (D)

Fight-or-flight responses are driven by hormones released during sympathetic activation, with adrenaline (epinephrine) from the adrenal medulla playing the primary role. This hormone rapidly mobilizes energy and prepares the body for quick action by increasing heart rate, widening airways, boosting glucose release into the blood, and redirecting blood toward muscles. The answer is the option that points to the hormone associated with this response because it identifies the central trigger of these widespread physiological changes. The other choices describe processes or substances not responsible for initiating the fight-or-flight surge (digestion-promoting hormones, insulin effects, or sleep-related neurotransmitters).