16. In the laboratory, recombinant plasmids are commonly introduced into bacterial cells by:
(A) electrophoresis – a gentle low-voltage gradient draws the DNA into the cell.
(B) infection with a bacteriophage that carries the plasmid.
(C)microinjection.
(D) mixing plasmids with an extract of broken cells.
(E) transformation - heat shock of the cells incubated with plasmid DNA in the presence of CaCl2.