( ( Adult lancelets ) ( ( retain ( key ( chordate characteristics ) ) ) . ) )
(ROOT (S (NP (JJ Adult) (NNS lancelets)) (VP (VBP retain) (NP (JJ key) (NN chordate) (NNS characteristics))) (. .)))
Adult lancelets retain key chordate characteristics.
(ROOT (S (NP (JJ Adult) (NNS humans)) (VP (VBP lack) (NP (NP (DT some)) (PP (IN of) (NP (NP (DT the) (VBG defining) (NNS traits)) (PP (IN of) (NP (NNS chordates))))))) (. .)))