Which of the following is an oxidation-reduction reaction? ZnS(s) + 2O2(g) ZnSO4(s) CaO(s) + H2O(l) Ca(OH)2(s) 6Li2O(s) + P4O10(g) 4Li3PO4(s) SO2(g) + H2O(l) H2SO3(aq)