What is the charge on $DNA$ and towards which electrode does it migrate during gel electrophoresis?

The correct order of steps in Polymerase Chain Reaction $(PCR)$ is

What is required for the expression of a foreign gene?

$I.$ In the process of recombinant $DNA$ technology,after several treatments,the purified $DNA$ is precipitated by adding chilled ethanol.
$II.$ The bacterial,plant,or animal cell is broken down by enzymes to release $DNA$,along with $RNA$,proteins,polysaccharides,and lipids.
Choose the correct option for the above statements.

Can a disease be detected before its symptoms appear? Explain the principle involved.

After staining,the $DNA$ fragments can be seen on the gel by exposing them to.......... light,which appear as.......... colored bands.