Sandra has to wait a few minutes after she enters a dark room before she can see anything around her. This is an example of.

The answer is sensory adaptation, more specifically dark adaptation.

Explanation:

Sensory adaptation refers to a decrease in the response to a certain stimulus. In other words, you become "used" to your environment.

The gradual improvement of sight in the dark is referred to as dark adaptation. Another example of this phenomenon is getting into a pool with cold water: in time, you should adapt to the temperature.