( Organisms ( ( ( need oxygen ) ( to ( ( release ( the energy ) ) ( from ( their food ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Organisms)) (VP (VBP need) (NP (NN oxygen)) (S (VP (TO to) (VP (VB release) (NP (DT the) (NN energy)) (PP (IN from) (NP (PRP$ their) (NN food))))))) (. .)))
Organisms need oxygen to release the energy from their food.
(ROOT (S (NP (NNS Plants)) (VP (CONJP (RB not) (JJ only)) (VP (VBP contribute) (NP (NN food))) (CC but) (VP (VBD oxygen) (PP (IN for) (NP (NNS organisms))))) (. .)))