What is the significance of adding proteases at the time of isolation of genetic material $(DNA)$?

Given below are four statements pertaining to the separation of $DNA$ fragments using gel electrophoresis. Identify the incorrect statements:
$(a)$ $DNA$ is a negatively charged molecule and so it is loaded on the gel towards the Anode terminal.
$(b)$ $DNA$ fragments travel along the surface of the gel,whose concentration does not affect the movement of $DNA$.
$(c)$ The smaller the size of the $DNA$ fragment,the larger is the distance it travels through it.
$(d)$ Pure $DNA$ can be visualized directly by exposing it to $UV$ radiation.
Choose the correct answer from the options given below:

$I.$ 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.

Which of the following is added to precipitate purified $DNA$?

When foreign $\text{DNA}$ is inserted into any vector,it results in inactivation of any marker gene. This is used for selection of $......\ :-$

Given below are two statements:
Statement $I:$ The $\text{DNA}$ fragments extracted from gel electrophoresis can be used in the construction of recombinant $\text{DNA}$.
Statement $II:$ Smaller size $\text{DNA}$ fragments are observed near the anode while larger fragments are found near the wells in an agarose gel.
In the light of the above statements,choose the most appropriate answer from the options given below: