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.

Input: Consider Input: 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.

Output: Science

Input: Consider Input: It exists because of electron degeneracy pressure; as electrons are compressed closer together, more exist per unit volume and must take on higher energy levels as mandated by the Pauli-exclusion principle. A relativistic state equation can be used to calculate it as the radius of a white dwarf decreases with an increase in its mass. Developed shortly before its namesakes theory on black holes, for ten points, name this value of about 1.4 solar masses, the maximum mass of a star which can be supported against gravitational collapse.

Output: Science

Input: Consider Input: One result of this effect was explained by the creation of quasiparticles in a quantum fluid by Laughlin, and Dyakonov and Perel predicted a version of it dependent on spin. It can be used to find hole density in a semiconductor, and von Klitzing showed that under certain situations this effect is quantized. This effect distinguishes between a negative current and a positive current flowing in the opposite direction, and it creates a Lorentz force, resulting in the deflection of charge carriers by a magnetic field. For 10 points, name this effect in which a potential difference is created across a conductor by a perpendicular magnetic field.
Output: Science