Which of the following is $NOT$ a characteristic of a plasmid?

Which of the following methods are used for the analysis of Restriction Fragment Length Polymorphism $(RFLP)$?
$1$. Electrophoresis
$2$. Electroporation
$3$. Methylation
$4$. Restriction digestion

Which of the following would not be used in preparing recombinant $DNA$?

The $DNA$ polymerase of $Thermus$ $aquaticus$ is:

Consider the following statements:
$I.$ $A$ soil-inhabiting plant bacterium,$Agrobacterium \; tumefaciens$,a pathogen of several dicot plants,is able to transfer a piece of $DNA$ known as $T-DNA$.
$II.$ The $T-DNA$ causes tumours.
$III.$ Tumour formation is induced by $Ti-plasmid$.
Which of the statements given above are correct?

$EcoRI$ derives from ..........