Which of the following is a non-conventional source of energy?

Which of the following statements about smog is/are correct?
$(i)$ Smog formed on sunny days contains oxidizing molecules.
$(ii)$ Photochemical smog contains many reactive molecules.
$(iii)$ The main polluting components of smog are oxides of carbon.
$(iv)$ The presence of carbon monoxide in air leads to the formation of ozone in smog.

The greenhouse effect is caused by which of the following?

Rain water is called as acid rain when its $pH$ is below

Which one of the following is mainly responsible for the depletion of the ozone layer?

Which term is used for the heat-trapping ability of greenhouse gases?