Final answer:
Marsha's adjustment to the temperature in the air-conditioned room is an example of sensory adaptation, where her perception of coldness decreases as her sensory receptors become less responsive to the unchanging stimulus.
Step-by-step explanation:
The change in the perception of coldness that Marsha experiences when entering an air-conditioned room and then adjusting to it can best be described as sensory adaptation. This phenomenon occurs when there is a decreased sensitivity to an unchanging stimulus over time. Initially, the cold air triggers sensory receptors that send signals to the brain leading to the perception of coldness. However, as Marsha remains in the room, her sensory receptors become less responsive to the constant temperature, resulting in a diminished perception of cold without any actual change in the environmental temperature itself. This sensory adaptation helps the body maintain perceptual efficiency by diminishing the awareness of nonthreatening, unchanging environmental stimuli.