teratoma. a type of germ cell tumor made up of a number of different types of tissue from one or more of the germ cell layers; it is usually found in the ovary or testis and may be either benign or malignant.
Bringing the effects of relaxation into our minds, television actually disturbs human brain and makes it tired even within the first minutes of TV watching session. Recent researches discovered that television slows down our thinking.
It is reasonable to think that the more TV you watch, the less time you spend studying, resulting in low test grades. However, it does not seem like these variables will be strongly correlated, since some people do not watch TV but do not spend time studying either.