The biosphere is:

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.

What is the greenhouse effect?

Which gaseous pollutant,even in low concentrations,causes respiratory distress such as inflammation and irritation in the human respiratory tract?

The conversion of hydroxyapatite occurs due to the presence of $F^{-}$ ions in water. The correct formula of hydroxyapatite is:

Which is the main component responsible for acid rain in the atmosphere?