About ten men in every hundred suffer from color1 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 forms of color1 blindness. In some cases a man can not see deep red. He may think that red, orange and yellow are all shades of green. Sometimes a person cannot tell the difference between blue and green. In rare cases an unlucky man may see everything in shades of green - a strange world indeed. Color blindness in human beings is a strange thing to explain. In a single eye there are millions of very small things called "cones". These help us to see in a bright light and to tell difference between color1s. There are also millions of "rods" but these are used for seeing when it is nearly dark. They show us shape but no color1. Some insects have favorite color1s. Mosquitoes   like blue but do not like yellow. A red light will not attract insects, but a blue lamp will. In a similar way human beings also have favorite color1s. Yet we are lucky. With the aid of the cones in our eyes we can see many beautiful color1s by day, and with the aid of the rods we can see shapes at night. One day we may even learn more about the invisible   color1s around. We can attract and kill mosquitoes by using a   _  .
red light yellow light .blue light green light