( ( ( Animal cells ) ( are different ) ) ( , ( they ( ( ( do not ) ( have ( cell walls ) ) ) . ) ) ) )
(ROOT (S (S (NP (NNP Animal) (NNS cells)) (VP (VBP are) (ADJP (JJ different)))) (, ,) (NP (PRP they)) (VP (VBP do) (RB not) (VP (VB have) (NP (NN cell) (NNS walls)))) (. .)))
Animal cells are different, they 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))))) (. .)))