Final answer:
The "fight-or-flight" response to stress is initiated by catecholamines, specifically epinephrine and norepinephrine, which prepare the body for immediate physical action.
Step-by-step explanation:
Fight-or-Flight Response Initiated by Catecholamines
The "fight-or-flight" response to stress is a critical reaction that enables an organism to confront or avoid danger. This physiological response is initiated by the secretion of epinephrine and norepinephrine from the adrenal medulla. These hormones, also known as catecholamines, rapidly prepare the body for immediate physical action, such as to fight off a threat or to take flight to evade danger. Activation of the sympathetic nervous system releases these hormones into the bloodstream, resulting in increased heart rate, blood pressure, blood glucose levels, and a series of other physiological changes that collectively prepare the body for a quick response to the stressor .When faced with the multiple choice question, the correct answer is: a. catecholamines. Steroids, glucocorticoids, and mineralocorticoids are all involved in the body's response to stress, but they mediate longer-term stress responses and are not the initiators of the acute fight-or-flight response.