Casey hears a rattling sound as she hikes through the desert. her muscles tense, her blood pressure rises, and her digestion shuts down. according to hans selye, she is in the:

Cassey is in the alarm phase. Hans Selye was a very important medical scientist working in the field of stress response. He developed the General Adaptation Syndrome, a model describing the three stages of a human's reaction in front of a threating situation. During the alarm stage, emergency signals are sent from the brain to the rest of the body and the body is getting ready to deal with the threat and fight or flight (escape).