Near the center of the retina there is a spot where there are no rods and no cones. This spot exists because of
A) clouding of the lens.
B) retinal degeneration.
C) the optic nerve.
D) the ciliary muscle.

Question

Quizplus · Accepted Answer

The spot without rods and cones in the center of the retina is called the optic disc, which is the location where the optic nerve exits the eye. Therefore, option C is the correct answer as the optic nerve is responsible for the absence of photoreceptors in this area. Options A and B are incorrect as they refer to conditions that do not affect the presence or absence of photoreceptors in the retina. Option D is incorrect as the ciliary muscle is responsible for adjusting the focus of the lens, not the absence of photoreceptors in the retina.

Near the Center of the Retina There Is a Spot