Feeling tired after a long day of work, you walk across a parking lot at night to get to your car. as you approach the car you see a shadow extending behind the back of the car. you immediately feel a rush of energy, your heart starts pounding, and you feel wide awake and alert. you slowly circle around to the back of the car and see that the shadow is coming from a parking lot sign above your car. you breathe a sigh of relief and start to calm down. you think about how you just felt in that scary situation and realize that you had the same reaction when you were called on in class to answer a question in front of everyone. your teacher used that exercise to describe that the hormone can be produced in fearful situations by