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...

Silencing of specific mRNA in RNAi is by

What is the first step in the Southern blot technique?

What is the process called when a foreign $DNA$ fragment replicates and multiplies automatically within a host organism?

What would happen when one grows a recombinant bacterium in a bioreactor but forgets to add antibiotic to the medium in which the recombinant is growing?

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?