Odd man out:

Concept: In an odd-one-out / classification question, three of the four given words share one defining property (a category, class, or role), while the fourth breaks that pattern; the task is to identify the shared property and see which option lacks it.

Application: Cornea, retina, and pupil are all physical, anatomical parts of the eye — the cornea is its transparent front covering, the retina is the light-sensitive layer lining its back, and the pupil is the opening in the iris that lets light in. Vision, however, is not a physical structure; it is the sensory function — the sense of sight — that these structures work together to produce.

• Cornea — a physical structure (the eye's transparent outer covering)

• Retina — a physical structure (the eye's light-sensitive inner layer)

• Pupil — a physical structure (the opening in the iris)

Vision is the only one of the four that is not a physical structure — it is the function these structures enable, so it does not fit the group.

Cross-check: Substitute any other eye part, such as lens or iris, in place of vision — it would still be a physical structure and would fit the group. Only a function/process word breaks the “anatomical structure” pattern, confirming the odd one out.