Which of the following statements is incorrect?

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

The blue and white selectable markers have been developed which differentiate recombinant colonies from non-recombinant colonies on the basis of their ability to produce colour in the presence of a chromogenic substrate.
Given below are two statements about this method :
Statement-$I$ : The blue coloured colonies have $\text{DNA}$ insert in the plasmid and they are identified as recombinant colonies.
Statement-$II$ : The colonies without blue colour have $\text{DNA}$ insert in the plasmid and are identified as recombinant colonies.
In the light of the above statements,choose the most appropriate answer from the options given below:

In gel electrophoresis,the separated $DNA$ fragments can be visualized by:

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: In recombinant $DNA$ technology, lysozyme is used for disrupting bacterial cells while cellulase is for plant cells.
Reason $R$: Isolation of genetic material needs disruption of cells.
In the light of the above statements, choose the most appropriate answer from the options given below:

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