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.

Leon Gambetta attempted to organize one side's defenses in this war, but fled in a hot air balloon. The Treaty of Frankfurt ended this war, in which the Battle of Sedan was fought. One cause of this war was the possibility of Leopold of Hohenzollern gaining the Spanish throne. Another cause of this war was an edited letter between the ambassador of one country in this war and Wilhelm I. That document known as the Ems Dispatch was used to advance the goals of Otto von Bismarck. For 10 points, name this 1870-1871 war between two European nations that led to German unification.
History

Lin and Shu proposed the density-wave theory to explain how the structure of these entities is sustained. The most accurate method for measuring the distances to distant ones uses a relation between their maximum rotational velocity and absolute magnitude, which is known as the Tully-Fisher method. They are generally blue because of their high content of old stars, and one type of them features arms that emanate from each end of a namesake structure. They have discs like the lenticular type, but contain much more angular momentum than the elliptical type. FTP name these galaxies, some of which are barred, including the Milky Way.
Science

One movement of this piece contains the refrain "Dark is life, is death," and it ends with the line "Blue lights the horizon / forever... forever..." The last movement contains notoriously difficult-to-execute instructions to disregard the tempo and spill over barlines. The third movement is in the ternary and pentatonic, "Of Youth," while the second movement laments dying flowers and fleeting beauty, "The Lonely Soul in Autumn. " This work features a horn theme in its "The Drunkard in Spring" movement, while the first movement is "The Drinking Song" of the land's misery. FTP, name this work inspired by the poetry of Li Po, a composition for two vocal soloists and orchestra by Gustav Mahler.

Fine Arts