Which of the following is $NOT$ a stage of sexual reproduction in fungi?

The reaction $RCOCl + H_2 \xrightarrow{Pd/BaSO_4} RCHO + HCl$ is known as:

$A$ sulphide ore is first converted into its oxide before reduction. This is done because

If $f:[-2,2] \rightarrow R$ is defined by $f(x) = \begin{cases} \frac{\sqrt{1+cx}-\sqrt{1-cx}}{x} & \text{for } -2 \leq x < 0 \\ \frac{x+3}{x+1} & \text{for } 0 \leq x \leq 2 \end{cases}$ and is continuous on $[-2,2]$,then $c$ is equal to

$A$ random variable $X$ takes the values $0, 1, 2, 3, \ldots$ with probability $P(X=x)=k(x+1)\left(\frac{1}{5}\right)^x$,where $k$ is a constant. Then $P(X=0)$ is

Companion cells are closely associated with $..........$.