Which one among the following is likely to have the highest levels of $DDT$ depositions in its body
Eel
Crab
Phytoplankton
Sea gull
Pyrethrin is a common ingredient of
The most common pesticide used in India is
$A$ : Barley, Sorghum and millet are smoother crops.
$R$ : They favour the growth of some common weeds.
By which of the following methods, new and better varieties of plants can be formed?
To which class of pesticides do DDT, BHC, aldrin and endosulphan belong