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.

In topological insulators, one version of this effect gives rise to a defect-resistant current induced by spin-orbit coupling. In graphene, this effect is shifted by one half, giving rise to an anomalous minimum of the relevant quantity, which can allow for ballistic transport. A more complex version of it was discovered in gallium arsenide and can be explained by Laughlin quasiparticles; this is referred to as the fractional version. This effect can be understood in terms of partial filling of Landau levels and has characteristic "plateaus", and it yields numbers called filling factors. Discovered by Klaus von Klitzing when studying a two-dimensional electron gas, for 10 points, identify this effect in which conductivity in a strong magnetic field is quantized.
Science

The enzyme LCAT catalyzes the formation of an ester from this compound. Intermediates in the synthesis of this compound include squalene [SKWAY-leen] and mevalonate [muh-VAL-uh-nate], the latter of which is produced by HMG-CoA reductase. Vitamin D is formed from the 7-dehydro form of this compound, which reduces membrane fluidity. This compound, which is transported to the liver by high-density lipoprotein, is linked to heart disease. For 10 points, name this compound whose amount in the blood is lowered by statins such as Crestor and Lipitor.
Science

Sensing his impending death, the only tenor in this opera bids his mother farewell with the aria "Addio alla madre," which comes not long after the drinking song, "Viva il vino. "  Mamma Lucia first learns of her son's affair from the aria, "Voi lo sapete," after which she runs into church and the ongoing Easter services. Following Lucia's exit, Santuzza argues with her lover and the subject of his new love, Lola. Passions over these women ultimately results in a duel in which Alfio kills Turiddu. Based on a story by Verga, FTP, name this epitome of verismo opera by Pietro Mascagni.

Fine Arts