Bacterial cells pick up free pieces of DNA from the medium-pieces that were released from dead bacteria-in a process called<span>. transformation.</span>
I recall that Professor Kwang had observed amoebas that had cannibalized bacteria cells. The bacteria were slaughtering the amoebas, but somehow some survived. This particular group of amoebas contained bacteria that thrived inside it. Hence the name, endosymbiosis. However, this lucky group and it's offspring could not survive without bacteria.
The answer is D. For producing recombinant, first you need to cut the insert part and vector part to get the same end by using restriction enzyme. Then using DNA ligase to bind these two parts to get a new plasmids.