In which method is recombinant $DNA$ directly injected into the nucleus of an animal cell?

Separated bands of $\text{DNA}$ in agarose gel electrophoresis observed under $\text{UV}$ radiation are stained with

It increases the efficiency with which $DNA$ enters the bacterium through pores in its cell wall.

In gel electrophoresis,the $DNA$ fragments separate according to ........

Assertion : Insertion of recombinant $DNA$ within the coding sequence of $\beta -$ galactosidase results in colourless colonies.
Reason : Presence of insert results in inactivation of enzyme $\beta -$ galactosidase known as insertional inactivation.

Which of the following should be chosen for best yield if one has to produce a recombinant protein or enzyme on a large scale,using microbial,plant,animal,or human cells?