Polymerase chain reaction employs

To isolate $DNA$ from fungi, the cell wall must be broken down. This process is carried out by which of the following enzymes?

$A$ : $DNA$ ligase plays an important role in recombinant $DNA$ technology.
$R$ : The linking of antibiotic resistance gene with plasmid vector became possible by enzyme $DNA$ ligase.

Which of the following sequences represents a palindromic $DNA$ sequence?

The method for separating $DNA$ fragments is . . . . . . .

$A$ - Cloning vectors are useful to transfer desirable $DNA$ into host cells.
$R$ - Agrobacterium tumefaciens is a pathogen of several dicot plants.