Answer:
e) An agent, such as a plasmid, used to transfer DNA from an in vitro solution into a living cell.
Explanation:
A cloning vector is a naked DNA that can be maintained and into which a foreign DNA can be inserted. A vector needs to be small in size, have restriction sites for endonuclease enzymes and the ability to multiply and express itself at a high rate, without disrupting the host cells machinery. Perfect cloning vectors are DNA molecules from viruses, plasmids and bacterial species such as E.Coli.
