The given figure is the diagrammatic representation of the $E. coli$ vector $pBR322$. Which one of the given options correctly identifies its certain component$(s)$?

What is the source of the $Ti$ (tumor-inducing) plasmid,which is modified and used as a cloning vector to deliver genes into plant cells?

Recombinant $DNA$ can be obtained by cutting pro-$DNA$ using:

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.

Restriction endonucleases are:

Choose the correct option based on the copy number capacity in a bacterial cell.