( Recognize ( ( that density ) ( ( is ( ( a ( characteristic property ) ) ( of matter ) ) ) . ) ) )
(ROOT (S (ADVP (RB Recognize)) (NP (DT that) (NN density)) (VP (VBZ is) (NP (NP (DT a) (JJ characteristic) (NN property)) (PP (IN of) (NP (NN matter))))) (. .)))
Recognize that density is a characteristic property of matter.
(ROOT (S (NP (NP (NNP Density)) (PP (IN of) (NP (NN matter)))) (VP (VBZ reflects) (SBAR (WHADVP (WRB how) (RB closely)) (S (VP (VBD packed) (SBAR (S (NP (NP (DT the) (NNS particles)) (PP (IN of) (NP (NN matter)))) (VP (VBP are)))))))) (. .)))