Question

The region in the eye where the rods and cones are located is the
A. Retina
B. Cornea
C. Choroid
D. Sclera

Answer 1

The eyes have photoreceptors, the cells that can sense the light, and rods and cones are the two types of photoreceptors that can sense the light as rods allow vision in low light especially in the dark while cons are responsible for the color vision and also the intensity of the color is regulated by them.

Complete answer:
Option A) The innermost layer of the fluid-filled eye is the retina containing photoreceptor cells: rods and cones which are responsible for dim and bright light and color vision respectively. To reach the retina light has to pass through many layers like the cornea, aqueous humor, anterior chamber, pupil, lens, and the vitreous humor so that a vision is formed at the retina. The amount of the light entered is controlled by changing size of the pupil but before striking the photoreceptors, the light travels through the sensory neurons, except fovea. The visual information is transmitted from photoreceptors to bipolar neurons and ganglion neurons before it excites the eye by the optic cranial nerve.
Option B) Out of the three layers of the fluid-filled spherical eye, cornea, and sclera form the outermost layer and cornea is the transparent layer that covers the pupil, iris, and anterior chamber of the eye. It controls and focuses the entry of the light in the eye as the iris controls the musculature of the pupil that controls its size and overall controls the amount of light entering the eye.
Option C) The middle layer of the fluid-filled spherical eye contains iris, the ciliary body, and the choroid out of which choroid is the vascular layer that consists of the connective tissue and is present between the retina and sclera.
Option D) Out of the three layers of the fluid-filled spherical eye, cornea and sclera form the outermost layer and sclera is the white part of the eyeball that is a hard protective covering who in coordination with cornea controls the movement of the eye muscles.

Hence, the correct answer is option (A).

Note:
Rod cells and cone cells differ in their shape, range of operation, distribution, connectivity, and visual function. Rods have higher convergence than cone as 120-rod cells send a signal to 1 ganglion cell while six cone cells send signals to one ganglion cell.