$A$ greenhouse is primarily used to grow plants during the $..........$ season.

Match the items in Column $A$ with those in Column $B$:
\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau\tau

Column $A$	Column $B$
$(A)$ Catalytic converter	$(i)$ Particulate matter
$(B)$ Electrostatic precipitator	$(ii)$ Carbon monoxide and nitrogen oxides
$(C)$ Earmuffs	$(iii)$ High noise level
$(D)$ Landfills	$(iv)$ Solid waste

$LPG$ cooking gas is

More than $70\; \%$ of the world's freshwater is contained in

Jhum cultivation:
$I.$ Also called as slash and burn agriculture,is the farming practice in North Eastern states of India.
$II.$ Farmers cut down the trees of forest and burn the plant remains.
$III.$ The ash is used as a fertilizer and the land is then used for farming or cattle grazing.
$IV.$ After cultivation,the land is left for several years,so as to allow its recovery.
Which of the statements given above are correct about Jhum cultivation?

Increase in concentration of a toxicant at successive trophic levels is called