( heterogeneous mixture )
(ROOT (NP (JJ heterogeneous) (NN mixture)))
heterogeneous mixture
(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)))))))))) (. .)))