Vision begins when light rays are reflected off an object and enter the eyes through the cornea, the transparent outer covering
of the eye. The cornea bends or refracts the rays that pass through a round hole called the pupil. The iris, or colored portion of the eye that surrounds the pupil, opens and closes (making the pupil bigger or smaller) to regulate the amount of light passing through. The light rays then pass through the lens, which actually changes shape so it can further bend the rays and focus them on the retina at the back of the eye. The retina is a thin layer of tissue at the back of the eye that contains millions of tiny light-sensing nerve cells called rods and cones, which are named for their distinct shapes. Cones are concentrated in the center of the retina, in an area called the macula. In bright light conditions, cones provide clear, sharp central vision and detect colors and fine details. Rods are located outside the macula and extend all the way to the outer edge of the retina. They provide peripheral or side vision. Rods also allow the eyes to detect motion and help us see in dim light and at night. These cells in the retina convert the light into electrical impulses. The optic nerve sends these impulses to the brain where an image is produced. You are looking at a brightly colored hot air balloon rise in the sunny sky. What is the path the light takes in order for you to see the balloon and the individual colors?
A) cornea - lens - pupil - retina - cones - optic nerve - brain - light
B) cornea - pupil - retina - cones - optic nerve - brain - light - lens
C) light - cornea - pupil - lens - retina - cones - optic nerve - brain
D) light - pupil - lens - cornea - retina - optic nerve - cones - brain
Eliminate
Organisms adapted and evolved the eyes to see the surrounding environment. This ability to see begins when the visible wavelength of light enters the eye through a transparent covering called Cornea. The light enters the cornea and enters the inner of the eye through a round hole known as the pupil.
The light rays then enters the convex-shaped lens in the eye which focuses the beam of light on the back of the eye in the region of the tissue called retina. The retina contains the photoreceptor cells-rods and cones in which the cone cells have the ability to detect three wavelengths of light especially blue, green and red which help us see various versions of the color.
These cells convert light energy to chemical energy in the form of the action potential which gets transmitted to the part of the brain associated with the vision. This completes the pathway of the vision
