( ( ( commonly used ) vectors ) ( ( are ( ( ( bacterial plasmids ) and ) ( viral phages ) ) ) . ) )
(ROOT (S (NP (ADJP (RB commonly) (VBN used)) (NNS vectors)) (VP (VBP are) (NP (NP (JJ bacterial) (NNS plasmids)) (CC and) (NP (JJ viral) (NNS phages)))) (. .)))
commonly used vectors are bacterial plasmids and viral phages.
(ROOT (S (NP (DT A) (JJ viral) (NN vector)) (VP (VBZ is) (NP (NP (DT the) (NN name)) (PP (IN for) (NP (NP (DT a) (NN tool)) (VP (ADVP (RB commonly)) (VBN used) (PP (IN by) (NP (JJ molecular) (NNS biologists))) (S (VP (TO to) (VP (VB place) (NP (JJ genetic) (NN material)) (PP (IN into) (NP (NNS cells))))))))))) (. .)))
A viral vector is the name for a tool commonly used by molecular biologists to place genetic material into cells.