( ( ( ELEMENT Substance ) ( which ( ( can not ) ( be ( ( ( broken down ) ( into ( simpler substances ) ) ) ( by chemical ) ) ) ) ) ) ( means . ) )
(ROOT (S (NP (NP (NNP ELEMENT) (NNP Substance)) (SBAR (WHNP (WDT which)) (S (VP (MD can) (RB not) (VP (VB be) (VP (VBN broken) (PRT (RP down)) (PP (IN into) (NP (JJR simpler) (NNS substances))) (PP (IN by) (NP (NN chemical))))))))) (VP (VBZ means)) (. .)))
ELEMENT Substance which cannot be broken down into simpler substances by chemical means.
(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))))))))))) (. .)))