Which of these reactions are redox reactions? Check all that apply.

Cd + HCl → CdCl2 + H2

CuCl2 + Na2S → 2NaCl + CuS

CaCO3 → CaO + CO2

2ZnS + 3O2 → 2ZnO + 2SO2

CH4 + 2O2 → CO2 + 2H2O