You will be given a definition of a task first, then some input of the task.
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.

One superacid shaped like an icosahedron features a skeleton almost entirely composed of this element. The selectrides are a group of reducing agents featuring this element bonded to three sec-butyl groups, and the nitrogen atom in proline binds to this element in the Corey-Bakshi-Shibata catalyst. Aryl- and vinyl- acids containing this element react with aryl- and vinyl-halides on catalytic palladium in the Suzuki reaction. Anti-Markovnikov addition is a feature of the best-known reaction featuring this element, in which an alkene is converted into an alcohol. That reaction features a namesake hydration followed by an oxidation and is catalyzed by a reactive compound consisting of this element bonded to three hydrogen atoms. For 10 points, name this fifth element.
Output:
Science