Definition: In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.
Input: The normal mechanism of the formation of these is altered in Chevrel and A15 phases. Generally, their constituents are not physically near each other, but are closely related in momentum space. A proposed method of splitting them is to send them through a carbon nanotube to form a Luttinger liquid. Evidence of their existence was supplied by the isotope effect, and the exchange of phonons results from their coupling. For 10 points -- name these groups that explain charge-carrier tunneling effects, paired electrons that form the basis of the BCS theory.
Output:
Science