Which 2 groups of substances below contain 1 element, 1 compound and 1 mixture? pick 2 groups. A.) Gold, sodium chloride, steel B.) oxygen, iodine, air C.) methane, iron(III)chloride, sea-water D.) Helium, carbon(IV) oxide, mixed dessert E.) Bronze, stainless steel, nitrogen(IV)oxide i pick B and D. can sombody correct me? what is STEEL under? mixture? thanks lotsa.