( ( Aromatic hydrocarbons ) ( ( are ( ( the ( most prevalent ) ) ( of ( ( the compounds ) ( definitely identified ) ) ) ) ) . ) )
(ROOT (S (NP (JJ Aromatic) (NNS hydrocarbons)) (VP (VBP are) (NP (NP (DT the) (ADJP (RBS most) (JJ prevalent))) (PP (IN of) (NP (NP (DT the) (NNS compounds)) (VP (ADVP (RB definitely)) (VBN identified)))))) (. .)))
Aromatic hydrocarbons are the most prevalent of the compounds definitely identified.
(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))))))) (. .)))