What is the function of (a) eye lens, (b) pupil (c) cones and rods

1.	What is the function of (a) eye lens, (b) pupil (c) cones and rods
Answer» <p>a)By changing its shape, thelenschanges the focal distance of the eye. In other words, it focuses the light rays that pass through it (and onto the retina) in order to create clear images of objects that are positioned at various distances. It also works together with the cornea to refract, or bend, light.</p> <p>b)Theiriscontracts and dilates involuntarily and changes the size of the pupil. The whole job of theirisand pupil is to control the amount of light that gets into the eye.</p> <p>c)</p><p>There are two types of photoreceptors involved in sight: rods and cones.</p><p>Rods work at very low levels of light. We use these for night vision because only a few bits of light (photons) can activate a rod. Rods don't help with color vision, which is why at night, we see everything in a gray scale. The human eye has over 100 million rod cells.</p><p>Cones require a lot more light and they are used to see color. We have three types of cones: blue, green, and red. The human eye only has about 6 million cones. Many of these are packed into the fovea, a small pit in the back of the eye that helps with the sharpness or detail of images.</p>

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