Roy and Roberts (Roy C, Roberts SL, 1981) developed a general theory of the person as an adaptive system, which may be considered a grand theory (Alligood MR, 2001) and separate middle-range theories of the four modes of adaptation the theory of the physiological mode, the theory of the self-concept mode, the theory of the role function mode, and the theory of the interdependence mode. The theory of the person as an adaptive system considers the person holistically. The theory of the physiological mode encompasses regulator subsystem responses related to exercise and rest, nutrition, elimination, fluid and electrolytes, oxygen and circulation, temperature, the senses, and the endocrine system. The theory of the self-concept mode, the theory of the role function mode, and the theory of...