Two bacteria found to be very useful in genetic engineering experiments are

$I.$ 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:

Nowadays, which of the following are known as "magic circles"?

Identify the enzyme shown in the given figure.

During 'gene cloning',which is called a gene taxi?

Today,we know more than $...$ restriction enzymes that have been isolated from over $...$ strains of bacteria.