Which of the following is not correct about carbon monoxide $(CO)$?

$A$ farmer is using pesticides in his field. He uses the produce from his field as food for fish. He is told that the fish are not fit for human consumption because large amounts of pesticides were found in the fish cells. How is this possible? Explain.

The compound that is $NOT$ a common component of photochemical smog is

Statues and monuments in India are affected by acid rain. How?

The maximum prescribed concentration of copper in drinking water is ........ $ppm$.

Some statements are given:
$(S_1) \ CO_2$ is a greenhouse gas.
$(S_2)$ Classical smog contains smoke,fog,and a high concentration of $SO_2$.
$(S_3) \ DDT$ is biodegradable.
$(S_4)$ Drinking water should have a high $B.O.D.$
Which is the correct sequence of true $(T)$ or false $(F)$ regarding the above statements?