( ( Their ( digestive ( and ( circulatory systems ) ) ) ) ( ( are merged ) . ) )
(ROOT (S (NP (PRP$ Their) (NN digestive) (CC and) (NN circulatory) (NNS systems)) (VP (VBP are) (ADJP (VBN merged))) (. .)))
Their digestive and circulatory systems are merged.
(ROOT (S (NP (NP (DT A) (NN relationship)) (PP (IN between) (NP (CD two) (JJ human) (NN body) (NNS systems)))) (VP (MD could) (VP (VB be) (NP (NP (DT the) (JJ digestive) (NN system)) (SBAR (S (VP (VBZ absorbs) (NP (NP (NNS nutrients)) (SBAR (WHNP (WDT which)) (S (VP (VBP are) (VP (VBN transported) (PP (IN by) (NP (DT the) (JJ circulatory) (NN system)))))))))))))) (. .)))