Final answer:
The structure in the human eye that acts as a light receptor is the cone. Cones are found in the retina, particularly concentrated in the fovea, and are essential for detailed vision in bright light and for color perception. The correct option is b.
Step-by-step explanation:
The structure that acts as a light receptor in the eye is the cone. These photoreceptor cells are responsible for detecting light and are situated in the retina of the eye. The retina is a light-sensitive layer that processes visual information and sends it to the brain through the optic nerve. Cones are particularly abundant in the fovea, which is a small indentation in the back of the eye known for having the highest concentration of cones. The fovea is part of the retina and is crucial for high-resolution vision in bright light conditions and for perceiving color.
The human eye is a complex organ designed for vision. Initially, light enters the eye through the cornea, which is the clear, protective outer layer. It then passes through the pupil, which is controlled by the iris to adjust the amount of light entering the eye. The light is further focused by the lens, which, together with the cornea, forms a real image on the retina. Given their ability to provide acute detail and color perception, cones play a fundamental role in the process of seeing. There are three types of cones (L, M, and S) each sensitive to different wavelengths of light. Unlike rods, which are more sensitive in dim light and do not provide color vision, cones are most effective under bright light conditions.
Other parts of the eye such as the sclera and uvea serve different functions. The sclera is the white, protective outer layer of the eye, and the uvea, which includes the iris, contributes to regulating the light that reaches the retina. The cochlea, mentioned as an option in the question, is an entirely different structure located in the inner ear that is responsible for hearing, not for light reception.