Which one of the following equipments is essentially required for growing microbes on a large scale for the industrial production of enzymes?

Who discovered $PCR$ (Polymerase Chain Reaction)?

The full form of $PCR$ is ...........

Consider the following statements:
$I.$ In microinjection method,foreign $DNA$ is directly injected into the nucleus of an animal cell or plant cell by using microneedles or micropipettes.
$II.$ Microinjection method is used in oocytes,eggs,and embryos.
$III.$ Electroporation is the formation of temporary pores in the plasma membrane of a host cell by using lysozyme or calcium chloride.
$IV.$ In chemical-mediated gene transfer method,certain chemicals such as $CO_{2}$ help foreign $DNA$ to enter the host cell.
Which of the statements given above are correct?

Give scientific reasons: Hepatitis $B$ and Bird flu $DNA$ vaccines are called Recombinant $DNA$ vaccines.

Gel electrophoresis is used for