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.

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.
Science

It holds only when the molecular attraction between different components is equal to the attraction of any one component in its pure state. Dealing primarily with changes in colligative properties, it allows for the calculation of molecular weights of dissolved substances and leads to the definition of a solution as ideal. FTP, identify this law that relates the vapor pressure and mole fraction of a solution, a law named for its French discoverer.
Science

One of this author's characters reads The Stones of Venice to learn English after meeting a woman who imagines dancing goblins while listening to Beethoven's 5th symphony. In that book, Leonard Bast dies of heart failure after being pushed into a bookcase by Charles Wilcox. A desire to switch hotel rooms begins a love affair between George Emerson and Lucy Honeychurch in one of this writer's novels. This author also wrote about the haunting echo of Marabar Caves, where Dr. Aziz is accused of raping Adela Quested. For 10 points, name this English author of Howard's End and A Passage to India.

Literature