Final answer:
The choroid is the eye layer responsible for supplying blood to the eye, particularly the outer retina, due to its highly vascularized tissue.
Step-by-step explanation:
The layer of the eye responsible for supplying blood to the eye is the choroid. The choroid is a layer of highly vascularized connective tissue that provides a blood supply to the eyeball, specifically the outer retina. The choroid is part of the vascular tunic, which includes other structures such as the ciliary body and iris. Moreover, the choroid is situated posterior to the ciliary body, which is a muscular structure attached to the lens and helps to focus light on the retina by bending the lens through zonule fibers.