Final answer:
In the alarm reaction phase of the general adaptation syndrome, the body shows the changes characteristic of the first exposure to a stressor.
Step-by-step explanation:
The alarm reaction phase of the general adaptation syndrome is characterized by the body's immediate reaction to a threatening situation or emergency. During this phase, the body experiences a cascade of physiological reactions that provide energy to manage the situation. The body shows the changes characteristic of the first exposure to a stressor. For example, if a person wakes up to discover their house is on fire, they are experiencing an alarm reaction.