Which of the following is required for the amplification of a gene of interest by $PCR$?

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

In which method is recombinant $DNA$ directly injected into the nucleus of an animal cell?

Which of the statements are correct about bioreactors?
$I.$ It provides all the optimal conditions for achieving the desired product by providing optimal growth conditions like temperature, $pH$, substrate, salt, vitamin and oxygen.
$II.$ It is suited for large-scale production of microorganisms under aseptic conditions for a number of days.

In the purification process of recombinant $DNA$ technology,what does the addition of chilled ethanol precipitate?

In gel electrophoresis,separated $DNA$ fragments can be visualized with the help of: