( ( polynuclear aromatic ) ( ( ( hydrocarbons ( -LRB- ( PAHs -RRB- ) ) ) ( ( ( ( ( a group ) , ) ( which ( includes ( ( naphthalene and ) biphenyls ) ) ) ) , ) ( of ( ( ( highly reactive ) ( organic compounds ) ) ( that ( are ( ( common components ) ( of ( ( creosotes , ) ( which ( can ( be carcinogenic ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NN polynuclear) (NN aromatic)) (VP (VBZ hydrocarbons) (PRN (-LRB- -LRB-) (NP (NNP PAHs)) (-RRB- -RRB-)) (NP (NP (NP (DT a) (NN group)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ includes) (ADJP (JJ naphthalene) (CC and) (JJ biphenyls))))) (, ,)) (PP (IN of) (NP (NP (ADJP (RB highly) (JJ reactive)) (JJ organic) (NNS compounds)) (SBAR (WHNP (WDT that)) (S (VP (VBP are) (NP (NP (JJ common) (NNS components)) (PP (IN of) (NP (NP (NNS creosotes)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (MD can) (VP (VB be) (ADJP (JJ carcinogenic)))))))))))))))) (. .)))
polynuclear aromatic hydrocarbons (PAHs) a group, which includes naphthalene and biphenyls, of highly reactive organic compounds that are common components of creosotes, which can be carcinogenic.
(ROOT (S (NP (DT A) (NN lipid)) (VP (VBZ is) (NP (NP (CD one)) (PP (IN of) (NP (NP (DT a) (ADJP (RB highly) (JJ diverse)) (NN group)) (PP (IN of) (NP (NP (NNS compounds)) (VP (VBN made) (PRT (RP up)) (ADVP (RB mostly))))) (PP (IN of) (NP (NNS hydrocarbons))))))) (. .)))