Final answer:
The choroid, ciliary body, and iris are structures of the vascular layer of the eye. The cornea and sclera are not part of the vascular layer but belong to the fibrous tunic.
Step-by-step explanation:
The structures that are part of the vascular layer, also known as the tunica vasculosa, of the eye include the choroid, ciliary body, and iris. The cornea and sclera, however, are part of the outermost layer called the fibrous tunic. The vascular tunic's primary role is to provide a blood supply to the eyeball and to facilitate the focusing of light. The choroid is a layer of highly vascularized connective tissue, the ciliary body is a smooth muscle structure that controls the shape of the lens through zonule fibers, and the iris is the colored part of the eye that regulates the size of the pupil in response to light intensity.