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

When did the Government of India introduce the concept of $JFM$?

In Maharashtra,a $24$-hour toll-free helpline number $1926$ has been set up to provide information regarding . . . . . . .

Approximately $P$ fraction of the solar radiation reaching the Earth is reflected by clouds and gases,and another $Q$ fraction is absorbed by them.

Consider the following statements about Ramesh Chandra Dagar's work in the field of organic farming:
$I.$ Ramesh Chandra Dagar's work includes bee-keeping,dairy management,water harvesting,composting,and agriculture in a chain of processes.
$II.$ In this process,there is no need to use chemical fertilisers for crops as cattle excreta is used as manure.
$III.$ Crop waste is used for making compost,which is used as natural fertilizer.
$IV.$ Compost generates natural gas,which is used for the energy needs of the farm.
Which of the statements given above are correct?

Which of the following plants is used for the purification of water?