Which of the following is a major component of water pollution?

What is the greenhouse effect?

$A$ large number of fish are suddenly found floating dead on a lake. There is no evidence of toxic dumping,but you find an abundance of phytoplankton. Suggest a reason for the fish kill.

Identify the incorrect statement from the following.

Which of the following conditions in drinking water causes methemoglobinemia?

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