Identify the types of smog that are oxidizing and reducing in nature.

The greenhouse gas(es) is/are:
$A$. Carbon dioxide
$B$. Oxygen
$C$. Water vapour
$D$. Methane
Choose the most appropriate answer from the options given below:

Which of the following protects life on earth from harmful effects of $UV$ radiations from the sun?

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:

Which of the following statement$(s)$ is (are) incorrect reason for eutrophication?
$A$. excess usage of fertilisers
$B$. excess usage of detergents
$C$. dense plant population in water bodies
$D$. lack of nutrients in water bodies that prevent plant growth
Choose the most appropriate answer from the options given below:

Which among the following statements is $NOT$ a principle of green chemistry?