Which one is a true statement regarding $DNA$ polymerase used in polymerase chain reaction?

EcoRI is

What is the term for a molecule that carries a desired gene into a host cell for cloning?

The first restriction endonuclease type $II$,$...A..$,was isolated by Smith,Wilcox and Kelley from $...B...$ bacterium. It was found to cut $DNA$ molecules at a particular point by recognizing a specific sequence of six base pairs,known as the $...C....$. Here $A, B$ and $C$ can be:

Molecular scissors are known as .....

Sticky ends are helpful in the action of which enzyme?