In the world of biotechnology and genetic engineering, what is a vector? a) a vector is a type of enzyme made by viruses, used to cut and splice dna fragments. b) a vector is a plasmid or virus used to move foreign genes into desired host cells. eliminate c) a vector is a type of gel used to move and separate dna fragments for dna fingerprints. d) a vector is a plasmid or virus used to perform the polymerase chain reaction and make copies of dna.