What do pesticides include?

In the following circuit,$PN$-junction diodes $D_1, D_2$ and $D_3$ are ideal. For the following potentials of $A$ and $B$,find the correct increasing order of equivalent resistance between $A$ and $B$:
$(i) V_A = -10\,V, V_B = -5\,V$
$(ii) V_A = -5\,V, V_B = -10\,V$
$(iii) V_A = -4\,V, V_B = -12\,V$

Which one of the following gases is liberated when ethyl alcohol is heated with methyl magnesium iodide?

$NH_3 + O_2 \xrightarrow[\Delta]{Pt} A + H_2O;$
$A + O_2 \to B$
$B + O_2 + H_2O \to C$
$A, B$ and $C$ are:

In $\Delta ABC,$ if $\cos A + \cos C = 4\sin^2\frac{B}{2},$ then $a, b, c$ are in

If $\alpha, \beta, \gamma$ are the roots of the equation $x^3-6x^2+11x-6=0$ and if $a=\alpha^2+\beta^2+\gamma^2$,$b=\alpha\beta+\beta\gamma+\gamma\alpha$ and $c=(\alpha+\beta)(\beta+\gamma)(\gamma+\alpha)$,then the correct inequality among the following is