( ( Animal cells ) ( ( ( do not ) ( have ( cell walls ) ) ) . ) )
(ROOT (S (NP (NNP Animal) (NNS cells)) (VP (VBP do) (RB not) (VP (VB have) (NP (NN cell) (NNS walls)))) (. .)))
Animal cells do not have cell walls.
(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))))) (. .)))