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.

This Vermont native's political positions included head of House and then Senate committees on territories, in which capacity he gave a speech telling opponents of expansion that "you cannot fetter the limbs of this young giant. " His support for expansion led him to favor repeal of the Missouri Compromise and he answered the Dred Scott decision by supporting popular sovereignty in what became known as the Freeport Doctrine. For 10 points, name this man who ran for president against John Bell, John C. Breckenridge and Abraham Lincoln, against the last of whom he had held a famous series of debates in Illinois.
History

proteins bind one end of these structures and help inhibit a process called "catastrophe. " These structures can have persistence lengths of 3-4 mm, which is several orders of magnitude higher than the average cellular diameter. These structures can be severed by katanin. Drugs such as paclitaxel stabilize these structures and prevent their depolymerization, where colchicine prevents its dimeric subunits from coming together. Shortening of these structure at the kinetochore ends of the spindle apparatus helps chromosomes walk towards poles during mitosis and meiosis. For 10 points, identify these structures which are components of the cytoskeleton and which are made of tubulin proteins.
Science

The presence of this element at the center of sarin allows it to inhibit acetylcholinesterase. This element bonds to an azide in the first step of the Staudinger reduction. A functional group containing this element in its center stabilizes the carbanion in the intermediate of the Horner-Wadsworth-Emmons reaction. Four atoms of this element bind to 10 oxygen atoms in its (*) pentoxide. A Z-alkene can be produced by reacting a carbonyl with an ylide with positive charge on this element in the Wittig reaction. Coming in notable white and red allotropes, for 10 points, name this element with atomic number 15 which is found below nitrogen on the periodic table.
Science