Question

the fight-or-flight response
the fight-or-flight response is initiated in response to what?
changes in blood pressure
vision impairment
perceived danger or threat
olfactory stimuli

Explanation:

The fight - or - flight response is a physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival. It is not primarily initiated by changes in blood pressure (which can be a result of the response), vision impairment, or olfactory stimuli.

Answer:

Perceived danger or threat