What do '$S$' and '$T$' represent in the given figure of a stirred-tank bioreactor?

What does $P$ represent in the given figure?

Consider the following statements:
$I.$ Recombinant $DNA$ technology,popularly known as genetic engineering,is a stream of biotechnology which deals with the manipulation of genetic material by man in vitro.
$II.$ $pBR322$ is the first artificial cloning vector developed in $1977$ by Bolivar and Rodriguez from $E. coli$ plasmid.
$III.$ Restriction enzymes belong to a class of enzymes called nucleases.
Which of the statements given above are correct?

What color does $X-gal$ produce in the presence of $\beta$-galactosidase?

$A$: $cDNA$ libraries are important to scientists in human genomics.
$R$: $cDNA$ is a synthetic type of $DNA$ generated from $mRNA$.

Identify '$Q$' and '$R$' in the given figure of a stirred-tank bioreactor.