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.

[EX Q]: After allying with the khan of Chagatai and taking part in campaigns in Transoxania, this ruler would lose a "muddy battle" against Ilyas Khodja, despite fighting alongside brother-in-law Husayn of Balkh. Becoming the head of the Barlas upon the death of Tughluk, this man annihilated Tokhtamysh and the Golden Horde at the Battle of the Terek River before he overwhelmed Sultan Mehmud's forces in seizing the Delhi Sultanate. Prior to his death and ultimate succession by Shah Rukh while planning an invasion of China, he defeated the Turks at the Battle of Ankara and captured Bayezid I. FTP, name this Mongol military leader who ruled in Central Asia during the 14th century from his capital of Samarkand.
[EX A]: History

[EX Q]: It is equal to the enthalpy change minus the temperature times the entropy change. Under standard conditions, it is also equal to negative R T times the natural log of K, where R is the gas law constant, T is the absolute temperature, and K is the equilibrium constant for the reaction; thus a high negative value indicates a forward-going reaction. FTP, identify this quantity, named for a Yale chemist, which is a measure of the spontaneity of a reaction.
[EX A]: Science

[EX Q]: MuSK acts with rapsyn to colocalize receptors for this molecule when it binds to the proteoglycan agrin found in the basal lamina. Binding of this molecule to those receptors causes a rotation of five transmembrane M2 helices. Alpha-bungarotoxin blocks the activity of this molecule, which is broken down by a namesake esterase rather than reuptaken in the synaptic cleft. The enzyme that catalyzes this molecule's synthesis is at abnormally low concentrations in Alzheimer's patients. Black widow venom stimulates excess release of this molecule, while botulinum toxin blocks its release; both result in paralysis. For 10 points, name this molecule found at the neuromuscular junction.
[EX A]:
Science