There are several times more rods than cones; with the help of them, the size, shape, outlines of objects are perceived even in poor lighting. The three main types of cones perceive red, blue, and yellow light.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.