( ( A ( heterogeneous mixture ) ) ( ( ( does not ) ( have ( ( a ( uniform composition ) ) ( throughout ( its mass ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (JJ heterogeneous) (NN mixture)) (VP (VBZ does) (RB not) (VP (VB have) (NP (NP (DT a) (JJ uniform) (NN composition)) (PP (IN throughout) (NP (PRP$ its) (NN mass)))))) (. .)))
A heterogeneous mixture does not have a uniform composition throughout its mass.
(ROOT (S (NP (NNS Heterogeneous)) (VP (VBZ is) (NP (NP (DT the) (NN term)) (PP (IN for) (NP (NP (DT a) (NN mixture)) (SBAR (WHNP (WDT that)) (S (VP (VBZ varies) (PP (IN in) (NP (PRP$ its) (NN composition)))))))))) (. .)))