Restriction endonuclease is used in

Which of the following enzyme$(s)$ are $\text{NOT}$ essential for gene cloning?
$A.$ Restriction enzymes
$B.$ $\text{DNA}$ ligase
$C.$ $\text{DNA}$ mutase
$D.$ $\text{DNA}$ recombinase
$E.$ $\text{DNA}$ polymerase
Choose the correct answer from the options given below:

What should a cloning vector $NOT$ possess?

The plasmid used for the construction of the first artificial recombinant $DNA$ molecule was obtained from which microorganism?

In $pBR322$,what does the letter '$p$' stand for?

Which of the following $DNA$ sequences can be cut by a restriction endonuclease?