The organism, which is used for gene transfer in higher plants is

The first restriction enzyme to be isolated and characterised was

$I.$ 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:

Which part of $Agrobacterium$ $tumefaciens$ is pathogenic?

Which organism is most commonly used as a host in $r-DNA$ technology?

In genetic engineering,the modification of $DNA$ has become possible due to the discovery of .............. .