The highest quantity present in the atmosphere is of

What changes take place in the $BOD$ of a water body with an increasing quantity of organic pollutants?

Which principle of green chemistry highlights that the protection of a selective group is not advantageous?

Dissolved oxygen is essential for aquatic life. What are the reasons responsible for the depletion of dissolved oxygen in water?

Assertion : Ozone is destroyed by $CFCs$ in the upper stratosphere. Reason : Ozone holes increase the amount of $UV$ radiation reaching the earth.

Given below are two statements :
Statement $I$ : If $BOD$ is $4\,ppm$ and dissolved oxygen is $8\,ppm$,then it is a good quality water.
Statement $II$ : If the concentration of zinc and nitrate salts are $5\,ppm$ each,then it can be a good quality water.
In the light of the above statements,choose the most appropriate answer from the options given below :