Pollution from animal excreta and organic waste from the kitchen can be most profitably minimised by

Identify the logic operation carried out by the following circuit.

Two electric charges of $9 \mu C$ and $-3 \mu C$ are placed $0.16 \ m$ apart in air. There will be a point $P$ on the line joining the two charges and in between them where the electric potential is zero. The distance of $P$ from the $9 \mu C$ charge is (in $m$)

The locus of the poles of focal chords of the parabola $y^2 = 4ax$ is

Endosperm is consumed by the developing embryo in the seed of

Which of the following compounds gives oxygen on fast heating?
$(I)$ $AgNO_3$
$(II)$ $CaCO_3$
$(III)$ $Pb(NO_3)_2$
$(IV)$ $Na_2CO_3$