Estuaries occur in which of the following Indian states?

$A$ lake near a village suffered heavy mortality of fishes within a few days. Consider the following reasons for this.
$A.$ Lots of urea and phosphate fertilizer were used in the crops in the vicinity.
$B.$ The area was sprayed with $DDT$ by an aircraft.
$C.$ The lake water turned green and stinky.
$D.$ 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?

Choose the correct answer from the given statements:
$(i)$ Sleeplessness
$(ii)$ Increases heart beat
$(iii)$ Altered breathing pattern

The concentration of an insecticide in the animals of a species is called:

Minerals,metals,and fossil fuels are which type of energy resources?

Arrange $CFC, CH_4, N_2O$ and $CO_2$ in decreasing order according to their contribution in the greenhouse effect.