What structure is comprised of the capsule, cortex, and nucleus?

The structure consisting of the capsule, cortex, and nucleus is the crystalline lens. The lens is a transparent, flexible structure located behind the iris and the pupil, playing a crucial role in focusing light onto the retina.

The capsule is a thin, transparent membrane that surrounds the lens, helping to maintain its shape and protect the inner components. The cortex is the outer layer of the lens, filled with elongated lens fibers that are responsible for the lens's ability to change shape during the process of accommodation—allowing the eye to focus on objects at varying distances. The nucleus is the central part of the lens, denser and harder than the cortex; it plays an essential role in the refractive properties of the lens.

Understanding this structure is vital in the context of vision and ocular health, as changes in the lens, such as those seen in cataracts, significantly impact a person's ability to see clearly. The other options—cornea, iris, and sclera—are different ocular structures and do not possess the specific layers of capsule, cortex, and nucleus as seen in the crystalline lens.