Which of the following pesticides does not inhibit cholinesterase?

According to the Euro-$III$ norms,what was the controlled limit for sulfur content in diesel (in $ppm$)?

What is the density of heavy metals?

What is meant by the aging of a lake?

The major source of noise pollution,worldwide,is due to:

$A$ - Micro-organisms involved in the biodegradation of organic matter in the receiving water body consume a lot of oxygen,and as a result,there is a sharp decline in dissolved oxygen in the stream from the point of sewage discharge.
$R$ - $BOD$ decreases when the dissolved oxygen amount decreases in water.