On Earth,all living organisms constitute:

The deposition of $X$ and $Y$ on ground surfaces is referred to as wet and dry depositions,respectively. $X$ and $Y$ are:

Which of the following causes "blue baby syndrome"?

Which of the given statements are correct, when carboxyhaemoglobin reaches $3-4 \%$ in blood?
$(I)$ Leads to headache
$(II)$ Results in cardiovascular problems
$(III)$ Increases the body temperature
$(IV)$ Leads to diarrhoea

Which of the following causes the depletion of the ozone layer in the stratosphere?

The correct statement about photochemical smog is .... .