Final answer:
The human eye is composed of three layers: the fibrous tunic, the vascular tunic, and the neural tunic. Each layer has specific structures that contribute to vision and photoreception.
Step-by-step explanation:
The human eye is a complex structure that consists of three layers: the fibrous tunic, the vascular tunic, and the neural tunic. The fibrous tunic includes the white sclera and the clear cornea, while the vascular tunic is composed of the choroid, ciliary body, and iris. The innermost layer, the neural tunic or retina, contains the nervous tissue responsible for photoreception.