Which of the following scientists are associated with the greenhouse effect?

Identify the correct statements from the following:
$i$. In the presence of $UV$ light,$CF_2Cl_2(g)$ gives chlorine free radicals which will react with $O_3(g)$ to form $O_2(g)$.
$ii$. Drinking water with $10 \ ppm$ fluoride is better than drinking water with $1 \ ppm$ fluoride.
$iii$. The maximum permissible concentration of lead in drinking water is $50 \ ppb$.

Which is not a renewable source?

The possibility of photochemical smog formation is more at

When the biosphere becomes an environment useful to humans,what is it called?

Rain water is called as acid rain when its $pH$ is below