What mucous membrane lines the eyelid and covers the anterior portion of the sclera?

The conjunctiva is a thin, transparent mucous membrane that plays an essential role in eye health. It lines the inner surface of the eyelids and extends over the anterior portion of the sclera, which is the white part of the eye. This membrane serves several important functions, including providing a protective barrier against pathogens, keeping the eye moist, and facilitating the movement of the eyelids across the eye surface, all of which are crucial for comfort and visual function.

The pupil, located in the center of the iris, is not a membrane but rather an opening that allows light to enter the eye. The cornea is the clear, front layer of the eye that helps focus light but does not cover the sclera. The retina is the light-sensitive layer at the back of the eye responsible for converting light into neural signals but is not involved in lining the eyelids or covering the sclera. Therefore, the conjunctiva is the only correct answer as it accurately describes the specific mucous membrane involved.