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.
Q: This two dimensional manifold is orientable and has Euler characteristic 0. It can be expressed as the product of two circles, but like the Klein bottle is more often viewed as a square with opposite sides identified. FTP, name this surface, which is more familiar to most people as the surface of a donut.
A:
Science