What is true for plasmid?

$Taq$ polymerase is isolated from a bacterium,$Thermus$ $aquaticus$.

Explain restriction enzymes and their nomenclature.

Which of the following is related to genetic engineering?

Identify the desirable characteristics for a plasmid used in $rDNA$ technology from the following.
$A$. Ability to multiply and express outside the host in a bioreactor.
$B$. $A$ highly active promoter
$C$. $A$ site at which replication can be initiated
$D$. One or more identifiable marker genes
$E$. One or more unique restriction sites.

$PCR$ technique was invented by