Select the incorrect statement regarding the continuous culture system.

$DNA$ precipitation out of a mixture of biomolecules can be achieved by treatment with

Silencing of specific mRNA in RNAi is by

On what basis are $DNA$ fragments separated in agarose gel electrophoresis?

Which of the following statements are correct with respect to $DNA$ separation, isolation and visualization?
$A$. The cutting of $DNA$ is done by molecular scissors.
$B$. The $DNA$ fragments separate according to their size in an agarose gel, upon electrophoresis.
$C$. The separated $DNA$ fragments can be seen without staining when exposed to $UV$ light.
$D$. The separated $DNA$ fragments, when stained with ethidium bromide, can be seen in visible light.
Choose the correct answer from the options given below:

During the process of isolation of $DNA$,chilled ethanol is added to