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.
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Question: 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.

Answer: Science


Question: The Act of Seclusion barred this man from holding office in one nation. Daniel Defoe wrote The True-Born Englishman in defense of this man. This man defeated much of his opposition with a victory at the Battle of the Boyne, and he agreed to the Bill of Rights. For 10 points, name this king of England who took power in the Glorious Revolution along with his wife Mary.

Answer: History


Question: Thalassemia patients have a reduced quantity of these cells, which can be measured using the mean corpuscular volume. The schizont phase of malaria is found within these cells. At the end of their lifespan, which is about 120  days, these cells are relocated to the spleen and destroyed. The body condition when a low number of these cells are present is anemia. These cells, which do not have nuclei, gain their color from an iron-containing protein known as hemoglobin. For 10 points, name these cells in the bloodstream, which carry oxygen throughout the body.

Answer:
Science