The layer of cells outside the phloem meant for giving rise to the root branches is called

In transgenics,the expression of a transgene in the target tissue is determined by:

When a capacitor is connected in series to an $LR$ circuit,the alternating current flowing in the circuit

In the equation $\log\, S = \log\, C + Z\, \log\, A$,what does $S$ represent?

If the pair of straight lines $xy-x-y+1=0$ and the line $ax+2y-3a=0$ are concurrent,then $a$ is equal to

If $a, b, c, d$ are positive real numbers such that $\frac{a}{3} = \frac{a+b}{4} = \frac{a+b+c}{5} = \frac{a+b+c+d}{6}$,then the value of $\frac{a}{b+2c+3d}$ is