Agarose gel electrophoresis is used to separate $DNA$ fragments. The $DNA$ fragments separate due to . . . . . . .

If a recombinant $DNA$ bearing a gene for resistance to Ampicillin is transferred into $E. coli$ cells,the host cells become transformed into Ampicillin-resistant cells. What happens when these $E. coli$ are grown on a medium containing Ampicillin?

What is downstream processing?

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

The method in which recombinant $DNA$ is directly injected into the nucleus of an animal cell by using microneedles is called:

Refer to the following statements for agarose-gel electrophoresis:
$(a)$ The $\text{DNA}$ fragments resolve according to their size.
$(b)$ The separated $\text{DNA}$ fragment can be visualised only after staining with ethidium bromide followed by exposure to $UV$ radiation.
$(c)$ $\text{DNA}$ is always loaded into the well.
$(d)$ The smallest fragment of $\text{DNA}$ is near the well.
Choose the correct statements: