Methane gas has a global warming potential approximately $25$ times that of which of the following gases?

Identify $X$,$Y$,and $Z$ in the following reaction. (Equation not balanced)
$ClO + NO_2$ $\rightarrow \underline{X}$ $\xrightarrow{H_2O} \underline{Y} + \underline{Z}$

Match List-$I$ and List-$II$:

List-$I$	List-$II$
$(a)$ Carbon monoxide	$(i)$ Carcinogenic
$(b)$ Sulphur dioxide	$(ii)$ Metabolized by pyrus plants
$(c)$ Polychlorinated biphenyls	$(iii)$ Haemoglobin
$(d)$ Oxides of nitrogen	$(iv)$ Stiffness of flower buds

Choose the correct answer from the options given below:

Ozone is a toxic gas and a strong oxidizing agent. However,it is essential in the stratosphere. Explain what would happen if it were to disappear completely from the stratosphere.

What is the troposphere,and which components are present in it?

If the concentration of nitrate in drinking water exceeds $45 \ ppm$,which disease is likely to occur in children?