The medication would be the controlled variable, the factor that remains constant.
The correct answer is resistance stage.
Hans Selye was a very important endocrinologist working in the field of biological stress. He developed the General Adaptation Syndrome (GAS) which is a model describing an animal's response to stress. GAS is comprised of three stages; the alarm, the resistance and the exhaustion stage.
During the resistance stage, the body's glands produce and secrete several hormones which protect the individual from the perceived stressor. Some of the hormones produced at this stage are the glucocorticoids.
Heterotrophs, primary consumers, and herbivores..