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

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:

What are bioreactors?

The Polymerase Chain Reaction $(PCR)$ is a reaction in which amplification of specific $DNA$ sequences is carried out in vitro. This statement is

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

Which one of the following statements is wrong with respect to separation of $DNA$ fragments on gel electrophoresis?