( ( ( ( ( Plants ( ( not only ) ( breathe ( out ( ( -LRB- ( respire -RRB- ) ) oxygen ) ) ) ) ) , ) but ) ( ( parts ( of ( their tissues ) ) ) ( also ( ( ( respire ( carbon dioxide ) ) , ) ( just ( as ( ( animals ( -LRB- ( heterotrophs -RRB- ) ) ) do ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (NNS Plants)) (ADVP (RB not) (RB only)) (VP (VB breathe) (PP (IN out) (NP (PRN (-LRB- -LRB-) (NP (NN respire)) (-RRB- -RRB-)) (NN oxygen))))) (, ,) (CC but) (S (NP (NP (NNS parts)) (PP (IN of) (NP (PRP$ their) (NNS tissues)))) (ADVP (RB also)) (VP (VBD respire) (NP (NN carbon) (NN dioxide)) (, ,) (SBAR (RB just) (IN as) (S (NP (NP (NNS animals)) (PRN (-LRB- -LRB-) (NP (NNS heterotrophs)) (-RRB- -RRB-))) (VP (VBP do)))))) (. .)))
Plants not only breathe out (respire) oxygen, but parts of their tissues also respire carbon dioxide, just as animals (heterotrophs) do.
(ROOT (S (NP (DT The) (NN heterotroph)) (VP (VBZ eats) (NP (UCP (ADJP (JJ only)) (CC or) (ADVP (RB mainly))) (NNS plants))) (. .)))