Answer: (a) The process of extracting a metal from its ore; (b) minerals from which a metal can be extracted profitably; (c) the earthy impurities mixed with an ore.
(a) Metallurgy is the whole process of obtaining a metal in a pure form from its ore — concentration of the ore, extraction of the metal and refining.
(b) Ores are those minerals of a metal which are found in the earth’s crust in sufficient quantity and from which the metal can be extracted conveniently and profitably. For example, bauxite (Al2O3·2H2O) is the ore of aluminium.
(c) Gangue is the unwanted material — sand, clay, rock and other impurities — present along with the ore. It is removed during concentration of the ore.