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]: This element's only oxidation state is -1, and it is impossible to free from its compounds by chemical means. It is prepared commercially be the same method which Henri Moisson used to isolate it in 1886, and is also found in the mineral cryolite. Its only isotope is the stabe 19 version, and in its gaseous form takes on a pale yellow color. The most electronegative and reactive of the elements, FTP, what is this lightest of the halogens with atomic number 9 and symbol F
[A]: Science


[Q]: Gravitational redshift was measured by Pound, Rebka, and Snider in Harvard's Jefferson Tower using this technique to detect a frequency shift of order one part in ten to the 14th. It can be used for precise studies of the Zeeman effect in nuclei. Iron 57 and tin 119 are two of the isotopes used in this type of spectroscopy due to narrow linewidths in their transitions. Before this technique, the large size of Doppler shifts relative to transition widths made nuclear spectroscopy problematic. It was discovered by its namesake when he was a graduate student at the Munich University of Technology. FTP, what is this effect in which a crystal lattice reduces recoil energy
[A]: Science


[Q]: Optical properties of this mineral include a change from biaxial positive to negative when its most common cation makes up 85% of its total cationic sum, and Poldervaart provided the most popular diagram for estimation of this mineral's composition based on birefringence and 2V, though optical geochemistry estimations often fail due to its compositional zonation. Conchoidal fracturing provides a route for its alteration to iddingsite, and its alpha form changes to wadsleyite and ringwoodite with increasing pressure, leading to use of its structure as a depth indicator for kimberlites. Substitution of manganese in its M1 site produces the rare variety tephroite. Mafic rocks such as gabbro or basalt contain it in abundance, since it is at the beginning of the discontinuous branch of Bowen's Reaction Series. FTP, name this nesosilicate whose end members include fayalite and forsterite, the most abundant mineral of the upper mantle, named for its particular shade of green.
[A]:
Science