( ( Chemical reactions ) ( ( occur ( in ( elements ( rearrange ( to ( form ( new substances ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Chemical) (NNS reactions)) (VP (VBP occur) (PP (IN in) (NP (NP (NNS elements)) (VP (VBN rearrange) (S (VP (TO to) (VP (VB form) (NP (JJ new) (NNS substances))))))))) (. .)))
Chemical reactions occur in elements rearrange to form new substances.
(ROOT (S (NP (PRP You)) (VP (VBP call) (NP (NP (DT a) (NN substance)) (SBAR (WHNP (WDT that)) (S (VP (MD can) (RB not) (VP (VB be) (VP (VBN broken) (PRT (RP down)) (PP (TO to) (NP (JJ other) (NNS substances))) (PP (IN by) (NP (NP (NN chemical) (NNS reactions)) (NP (DT an) (NN element))))))))))) (. .)))