What is $pBR322$?

Following statements describe the characteristics of the enzyme Restriction endonuclease. Identify the Incorrect statement.

$I.$ Bacteriophages are $...A...$ infecting $...B....$
$II. ...C...$ are hybrid vectors derived from plasmids which contain $cos$ site of $\lambda$ phage.
$A, B$ and $C$ in above statements refer to:

What should a cloning vector $NOT$ possess?

Cutting of a piece of $DNA$ from a plasmid was done with the help of $...A...$ enzymes,popularly known as $...B....$ Here $A$ and $B$ can be

$K_{12}$ plasmid was studied first in