First question :

Black and white can be considered to be nuances of a single color. What is a color television? A color television is a television that can display multiple colors. However, black and white can be considered to be nuances of the same color. Thus, it would be a stretch to say that a black and white television is a color television, because it cannot display multiple colors, only a single one. However, it could be called a single color television. However, this distinction between B&W and color television could simply be a random result of language use. That would mean that this usage is simply the result of convention, rather than of an objective reason. The way we name things is often slightly random. The more appropriate linguistic term is to say that it is arbitrary, as opposed to motivated. For instance, some b&W televisions weren't truly black and white, instead they often had a slight bluish tint. On the other hand, a color television is still called a color television even if it displays B&W content.