Which of the following is related to genetic engineering?

$I.$ 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 enzyme is not used for $DNA$ isolation in animal cells?

Which of the following is a suitable vector for gene cloning in higher organisms?

In the $PCR$ technique,the amplification of a $DNA$ segment is carried out by which enzyme?

Which statement is correct regarding the $DNA$ polymerase used in $PCR$?