What is the correct sequence of atmospheric layers starting from the Earth's surface?

Given below are two statements :-
Statement $I :$ The value of the parameter "Biochemical Oxygen Demand $(BOD)$" is important for survival of aquatic life.
Statement $II :$ The optimum value of $BOD$ is $6.5 \ ppm$.
In the light of the above statements,choose the most appropriate answer from the options given below:

How can you apply Green Chemistry for the following?
$(a)$ To reduce photochemical smog.
$(b)$ To avoid the use of chlorinated solvents and chlorinated bleaching agents in dry cleaning.
$(c)$ To reduce the use of synthetic detergents.
$(d)$ To reduce the consumption of petrol and diesel.

What are the harmful effects of photochemical smog and how can they be controlled?

What is the reagent used for testing fluoride ion in water?

$ODS$ is used in .....