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The eye is the organ that has the ability to detect light. The human eye is able to distinguish between different shapes and colors. The human eye also has better depth perception than many other animals.
When the eye looks at an object, light rays come through the transparent cornea, enter the pupil and are focused on the retina by the lens. The light rays are bent when they enter the eye and the lens' job is to make sure the rays come to a sharp focus on the retina. Light-sensitive nerve cells called rods (for brightness) and cones (for color) react to the light and send messages to the brain that indicate brightness, color, and shape.
The image that lands on the retina when it first enters the eye is upside-down. The light rays on the retina are converted to electrical impulses which are then transmitted through the optic nerve, to the brain, where the image is decoded and turned right side up!
Almost all animals have eyes, or descend from animals that did. |
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