Answer:
The fight-or-flight-or-freeze or the fight-flight response (also called hyperarousal or the acute stress response) is a physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival.
I believe its large blue vessel also known as vena cava
The skeletal system does not digest. That is the job of the digestive system. Hope this helps!
An intrusion is the action of intruding or intruding. I hope I helped a little!! :-)
