Which selection method is used for vegetative propagation in plants?

In the given transistor circuit,the base current is $35\,\mu A$. The value of $R_b$ is.......$k\Omega $

If $\cos (x-y), \cos x, \cos (x+y)$ are three distinct numbers which are in harmonic progression and $\cos x \neq \cos y$,then $1+\cos y$ is equal to

Semi-water gas is a mixture of which of the following?

If ${}^n P_r = 30240$ and ${}^n C_r = 252$,then the ordered pair $(n, r)$ is equal to

In a $P-N$ junction diode,if the $P$ region is more heavily doped than the $N$ region,then the depletion layer is: