Hi, I am stuck on three, can anyone help please? 21D Impure mixture of metal sulphides produced during the smelting of sulphide ores, especially those of copper and nickel. M-T-E 27D Diocese of the pope as bishop of rome and head of the church 4/3 --L- S-E 32D In geometry, a fixed reference point on the concave side of a conic section --C-S HELP!