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.

The blende of this element is used as a model crystal structure for semiconductors like indium
phosphide. In one reaction, this element is used with alpha-halo esters to condense ketones or aldehydes to
form beta-hydroxy-esters. When coupled with copper, this element reacts with alkenes to yield a
cyclopropane. Those reactions are named for Reformatsky and Simmons-Smith. Found in the ore
sphalerite, this element and hydrochloric acid reduce ketones to alkanes in the Clemmensen reduction. In
proteins, this element makes "gag-knuckles," "treble-clefs," and other structures known as "fingers."
Galvanized steel is coated in this element, and brass is an alloy of copper and this element. For 10 points,
name this element with number 30 and symbol Zn.
Science