( ( ( ( ( ( Each window ) ( can ( ( ( display up ) ( to ( six substances ) ) ) simultaneously ) ) ) , ) and ) ( ( multiple tracers ) ( may ( be ( invoked ( to ( observe ( ( all substances ) ( of interest ) ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (DT Each) (NN window)) (VP (MD can) (VP (VB display) (PRT (RP up)) (PP (TO to) (NP (CD six) (NNS substances))) (ADVP (RB simultaneously))))) (, ,) (CC and) (S (NP (JJ multiple) (NNS tracers)) (VP (MD may) (VP (VB be) (VP (VBN invoked) (S (VP (TO to) (VP (VB observe) (NP (NP (DT all) (NNS substances)) (PP (IN of) (NP (NN interest))))))))))) (. .)))
Each window can display up to six substances simultaneously, and multiple tracers may be invoked to observe all substances of interest.
(ROOT (S (NP (DT A) (NN tracer)) (VP (VBZ is) (NP (NP (DT the) (NN name)) (PP (IN for) (NP (NP (DT a) (NN substance)) (SBAR (WHNP (WDT that)) (S (VP (MD can) (VP (VB be) (VP (VBN used) (S (VP (TO to) (VP (VB follow) (NP (NP (DT the) (NN pathway)) (PP (IN of) (NP (DT that) (NN substance)))) (PP (IN through) (NP (DT some) (NN structure))))))))))))))) (. .)))