What is the role of the pupil in visual perception, and how does it adapt to different lighting conditions?

• A. It changes shape to focus light; adapts by shifting position
• B. It protects the eye from UV light; adapts by thickening
• C. It regulates light entry; adapts by dilating in dim light and constricting in bright light
• D. It processes color vision; adapts by altering sensitivity

Answer: (C)