In the presence of a chromogenic substrate,what color colonies do recombinants and non-recombinants produce,respectively?

If a recombinant $DNA$ molecule carrying an ampicillin resistance gene is introduced into an $E. coli$ cell and the host cells are spread on an agar plate containing ampicillin,then...

Assertion : Insertion of recombinant $DNA$ within the coding sequence of $\beta -$ galactosidase results in colourless colonies.
Reason : Presence of insert results in inactivation of enzyme $\beta -$ galactosidase known as insertional inactivation.

$DNA$ can be introduced into any cell by:

Which of the following diagrams is correct for primer annealing in $PCR$?

Consider the following statements about $PCR$:
$I.$ Polymerase Chain Reaction $(PCR)$ is a technique of synthesizing multiple copies of the desired gene in vitro.
$II.$ This technique was developed by Kary Mullis in $1985$.
$III.$ $A$ single $PCR$ amplification cycle involves three basic steps: denaturation,annealing,and extension.
Which of the statements given above are correct?