( ( Plant cells ) ( ( ( possess ( ( ( a ( cell wall ) ) , ) animals ) ) never ) . ) )
(ROOT (S (NP (NNP Plant) (NNS cells)) (VP (VBP possess) (NP (NP (DT a) (NN cell) (NN wall)) (, ,) (NP (NNS animals))) (ADVP (RB never))) (. .)))
Plant cells possess a cell wall, animals never.
(ROOT (S (NP (DT A) (NN cell) (NN wall)) (VP (VBZ is) (RB not) (ADJP (JJ present) (PP (IN in) (NP (NN animal) (NNS cells))))) (. .)))