The living organisms or the surroundings of the earth's composition are known as .....

The statements that are $TRUE$:
$A$. Methane leads to both global warming and photochemical smog.
$B$. Methane is generated from paddy fields.
$C$. Methane is a stronger global warming gas than $CO_2$.
$D$. Methane is a part of reducing smog.
Choose the most appropriate answer from the options given below:

London smog is found in

What is Eutrophication?

What are the reactions involved for ozone layer depletion in the stratosphere?

In drinking water,if the maximum prescribed concentration of copper is $x \ mg \ dm^{-3}$,the maximum prescribed concentration of zinc will be