About ten men in every hundred have the trouble of color blindness in some way. Women are luckier, only about one in two hundred is affected in this matter. Perhaps, after all ,it is safer to be driven by a woman. There are different kinds of color blindness. For example, a man cannot see deep red. He may think that red, orange and yellow are all shades   of  green. Sometimes a person can't tell the difference between blue and green. Only a few unlucky men may see everything in shades of green-- a strange world indeed. Color blindness in human beings is a different thing to explain. In only one eye there are millions of very small things called "cones " . These help us to see in the bright light and to tell differences between colors. These are also millions of "rods" ,but these are used for seeing when it is nearly dark. They show us shapes but not colors. Some insects have favorite colors. Mosquitoes  like blue but do not like yellow. A red light will not attract insects, but a blue light will. Human beings also have favorite colors. Yet we are lucky. With the help of the cones in our eyes, we can see many beautiful colors by day, and with the help of the rods we can see shapes at night. We can attract and kill mosquitoes by using a  _  light.
red yellow blue green