Identify the correct sequence of steps in each cycle of Polymerase Chain Reaction $(PCR)$:

Which of the following cannot be used for direct gene transfer?

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?

In $pBR322$,foreign $DNA$ is inserted using the restriction enzyme $Cla\, I$. If this recombinant plasmid is introduced into bacteria,which of the following will occur regarding growth on antibiotic-containing media?

For selection of recombinants,insertional inactivation of antibiotic marker has been superceded by insertional inactivation of a marker gene coding for a chromogenic substrate. Give reasons.

$A$ transformed bacterium with a human gene fails to produce the desired protein. The reason could be: