Answer:
...because it can take a long time for dark adaptation to occur.
Explanation:
Dark adaptation is the ability of the visual system to adjust to new levels of illumination, recovering sensitivity after exposure to light - such as when we go from the outdoors to the indoors. This process of adjustment includes the dilation of the pupil, as well as an increase in sensitivity of the retinal rods, even though the recovery is faster in the cones.
