Which of the following is $NOT$ included in the downstream processing of recombinant $DNA$ technology?

Palaeontologists unearthed a human skull during excavation. $A$ small fragment of the scalp tissue was still attached to it. Only a little $DNA$ could be extracted from it. If the genes of the ancient man need to be analysed,the best way of getting a sufficient amount of $DNA$ from this extract is:

Give scientific reasons: The products prepared by recombinant $DNA$ technology have to undergo downstream processing.

The components of a bioreactor are:
$I.$ An agitator system
$II.$ An oxygen delivery system
$III.$ Foam control system
$IV.$ Temperature control system
$V.$ $pH$ control system
$VI.$ Sampling ports to withdraw cultures periodically
Choose the correct option.

Which of the following steps is/are catalysed by $Taq$ polymerase in a $PCR$?

$DNA$ can be introduced into any cell by: