When During the alarm stage what substance does the body release that triggers responses to a threat?

During the alarm stage of the stress response, the body releases adrenaline (epinephrine) and norepinephrine. These hormones are produced by the adrenal glands and trigger physiological responses such as increased heart rate, heightened alertness, and enhanced energy availability, preparing the body to confront or flee from the perceived threat. This response is part of the "fight or flight" mechanism.