Which of the following is not a part of the human eye?

The incus is not part of the human eye; it is one of the three small bones in the middle ear, playing a crucial role in the process of hearing by transmitting sound vibrations from the eardrum to the inner ear.

In contrast, the cornea, retina, and pupil are all essential components of the eye. The cornea is the transparent front part of the eye that helps to focus light. The retina is the layer of tissue at the back of the eye that converts light into neural signals for the brain to interpret. The pupil is the opening in the center of the iris that adjusts its size to control the amount of light entering the eye. Understanding these distinctions helps clarify anatomical functions and the relevance of each part in the visual system.