Part 1 of Essay
Color blindness is the inability to distinguish particular colors. It is generally an inherited trait, but can result from a chemical imbalance or eye injury. There are three primary colors. They are red, blue, and yellow. All other colors are the results of different combinations of primary colors. Special visual cells ....

Part 2 of Essay
.... monochromatic vision has just one type of cone, and can see just one color, and various shades of that color. This form is even rarer than the "typical" monochro-matism. Another, more common, form of color blindness is called dichromatism. People with di-chromatic vision tend to confuse red, green, and gray, but can easily distinguish blue and yellow. Some cannot even see the longest wavelengths of light -- the red end. Though it is rare, others cannot see the short wavelengths, near the violet end. The ....