Answer:
Transformation,inserting of the Human DNA into the bacterial genome
Explanaion:
Some bacterial cells are not transgenic, and therefore do not take the foreign human DNA, These untransformed bacteria are removed by markers.
This stage is most difficult because the new bacterial cell must be formed from the transformed single bacterial cell.However,bacteria is unicellular unlike human cells and do not need regeneration but binary division ( cloning). ,Therefore not all the new daughter bacterial cells will imbibe the inserted genetic materials as single human DNA materials to be transformed to.
The production occurs randomly, and some do not take the human genetic materials.