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: When it interacts with ryanodine receptors, this element upregulates its own release, and this compound forms the cell plates of coccolithophores. Stimulation of Gq ("g-sub-q") opens a channel that allows for this ion's movement, and proteins that bind this ion have an EF hand motif. Cellular concentrations of this ion are regulated by IP3. Parafollicular cells of the (*) thyroid produce a compound that reduces the concentration of this ion in blood, and its intestinal absorption requires vitamin D. This ion interacts with Troponin to stimulate muscle contraction, and the lumens of sarcoplasmic reticula have high concentrations of this ion. For 10 points, name this divalent cation that is stored in bones.

A: Science
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Q: One member of this phylum, Strongylocentrotus purpuratus, is often used to study developmental processes, and another, Pisaster ochraceus, is an example of a keystone species. Most members of this phylum have pedicellariae that possess three jaws, and some have a chewing apparatus known as Aristotle's lantern. Members of class Asteroidea of this phylum have an ambulacral groove, and the madreporite is the entrance to their water vascular system that includes tube feet. FTP name this phylum whose "spiny skinned" members have radial symmetry and include sand dollars, sea urchins, and sea stars.

A: Social Science
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Q: In an early scene in this work, the protagonist recounts an affair he had with Monique, a prostitute, and that protagonist later writes down the license plate number of a car that he suspects is following him. One character in this work plays a farmer's daughter in The Enchanted Hunters, a play which shares its name with a hotel. That character is abducted from a hospital by the(*) playwright Clare Quilty, whom the narrator later tracks down and kills. For 10 points, identify this novel in which Humbert Humbert lusts after the underaged "nymphet" Dolores Haze, written by Vladimir Nabokov.

A:
Literature
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