Select the appropriate option regarding the natural aging of a lake.

Which one of the following is the correct percentage of the two (out of the total of $4$) greenhouse gases that contribute to the total global warming?

What is $FOAM$?

Ecological backlash (or Ecological Boomerang) is:

The most common pesticide used in India is

$A$ lake near a village suffered heavy mortality of fishes within a few days. Consider the following reasons for this:
$1.$ Lots of urea and phosphate fertilizer were used in the crops in the vicinity.
$2.$ The area was sprayed with $DDT$ by an aircraft.
$3.$ The lake water turned green and stinky.
$4.$ Phytoplankton populations in the lake declined initially,thereby greatly reducing photosynthesis.
Which two of the above were the main causes of fish mortality in the lake?