Which impurities are released along with $DNA$ when cells are broken down for $DNA$ isolation?

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:

Can you think and answer how a reporter enzyme can be used to monitor transformation of host cells by foreign $DNA$ in addition to a selectable marker?

Which of the following statements is correct in the context of observing $DNA$ separated by agarose gel electrophoresis?

Significance of heat shock method in bacterial transformation is to facilitate

Production of a human protein in bacteria by genetic engineering is possible because