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]: A namesake protein component of this structure is detected by Toll-like Receptor 5. Tg737, whose mutation causes polycystic kidney disease in mice, is responsible for transport within this structure, which is also dependent upon complexes of IFT proteins. Y. Pestis uses a structure homologous to these to inject virulence factors into host cytoplasm, known as the Type III secretory system. They have a P, L, and MS ring in gram-negative bacteria, and in all organisms their central body is called the axonene. In Eukaryotes, they contain a 9+2 set of microtubules around a central pair and use dyenin and ATP hydrolysis to power their whipping motion. Similar to cilia, for 10 points, name these projections used by cells to swim.
[EX A]: Science

[EX 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
[EX A]: Science

[EX Q]: According to the myths of the Navajo and Pueblo, the world was created by an old woman who took the form of this creature. In the myth of the Lakota, dreamcatchers were created by a god in the shape of this animal named Iktomi. Another one of these creatures was a son of Asase Ya who brought back a leopard, snake, dwarf, and hornet before his father Nyame gave him all the (*) stories in the world. Athena turned a woman into one of these animals after she depicted the affairs of the gods in her weaving. In West African folklore, the trickster god Anansi was one of these creatures. For ten points, name this eight-legged animal that Arachne was turned into.
[EX A]:
Social Science