I do not recall ever seeing someone fail at knock knock jokes before. "shakes head"

    In the article, Color Blindness: Psychological Effects, Jessika Bailey describes what color blindness is and how it affects the psychology of a person who is afflicted 由 this disability. Color blindness is when one, two, 或者 all retinal photoreceptors, 或者 cones, in someone’s eyes are damaged 或者 not working in some way. Bailey explains that this is usually caused 由 a mutated X chromosome. Men that have one of this mutated chromosome get color blindness, and women must have two of this chromosome to get the disability as well. There are three types of cones in someone’s...