Which reaction type is really part of another type of reaction but treated separately? Explain

Which of these reactions are redox reactions? check all that apply.cd + hcl → cdcl2  + h2cucl2  + na2s → 2nacl + cuscaco3  → cao + co2          2zns + 3o2  → 2zno + 2so2          ch4  + 2o2  → co2  + 2h2o

How would you reduce the volume of gas

Which element would mostly likely have an electron affinity measuring closest to zero