1. Which part of the eye controls the amount of light entering? a) Comea b) Iris c) Retina d) Lens

The correct answer is b) Iris.<br /><br />The iris is the colored part of the eye that controls the amount of light entering the eye. It does this by adjusting the size of the pupil, which is the opening in the center of the iris. When the iris is exposed to bright light, it contracts, making the pupil smaller and reducing the amount of light that enters the eye. Conversely, in low light conditions, the iris expands, making the pupil larger and allowing more light to enter the eye. This helps the eye adjust to different lighting conditions and maintain optimal vision.