( Density ( ( is ( ( a measure ) ( of ( ( how much ) ( ( matter ( -LRB- ( mass -RRB- ) ) ) ( there ( is ( in ( ( a ( given amount ) ) ( of ( space ( -LRB- ( volume -RRB- ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Density)) (VP (VBZ is) (NP (NP (DT a) (NN measure)) (PP (IN of) (SBAR (WHADJP (WRB how) (JJ much)) (S (NP (NP (NN matter)) (PRN (-LRB- -LRB-) (NP (NN mass)) (-RRB- -RRB-))) (ADVP (RB there)) (VP (VBZ is) (PP (IN in) (NP (NP (DT a) (VBN given) (NN amount)) (PP (IN of) (NP (NP (NN space)) (PRN (-LRB- -LRB-) (NN volume) (-RRB- -RRB-)))))))))))) (. .)))
Density is a measure of how much matter (mass) there is in a given amount of space (volume).
(ROOT (S (NP (NNP Density)) (VP (VBZ describes) (SBAR (WHADJP (WRB how) (JJ much)) (S (NP (NN matter)) (VP (VBZ is) (PP (IN in) (NP (NP (DT a) (JJ certain) (NN amount)) (PP (IN of) (NP (NN space))))))))) (. .)))