'Bad' ozone is formed in

Acoustic zoning is related to:

Choose the correct option for catalytic converters.

Excess of which of the following in drinking water causes mottling of teeth?

Which of the following acts as a secondary pollutant?

Observe the figure and answer the following questions.
$(i.)$ What ecological term is used to describe the $DDT$ accumulation at different trophic levels?
$(ii.)$ List any one effect of $DDT$ accumulation on birds.
$(iii.)$ Will $DDT$ accumulation lead to eutrophication?
$(iv.)$ Does it affect the $BOD$?
$(v.)$ Name a disease caused by the accumulation of any heavy metal.