What are the full forms of $ELISA$ and $PCR$?

In the $PCR$ technique,how are the two strands of $DNA$ separated?

What type of method is the $PCR$ technique?

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?

Which of the following steps are involved in the process of recombinant biotechnology? Arrange in correct order.
$I.$ Extraction of the desired gene product
$II.$ Amplification of the gene of interest
$III.$ Isolation of a desired $DNA$ fragment
$IV.$ Ligation of the $DNA$ fragment into a vector
$V.$ Insertion of recombinant $DNA$ into the host
Correct order is:

The preparatory phase before fermentation is known as: