( ( a -RRB- ) ( ( The ( circulatory system ) ) ( ( transports ( substances ( around ( the body ) ) ) ) . ) ) )
(ROOT (S (LST (LS a) (-RRB- -RRB-)) (NP (DT The) (JJ circulatory) (NN system)) (VP (VBZ transports) (NP (NP (NNS substances)) (PP (IN around) (NP (DT the) (NN body))))) (. .)))
a) The circulatory system transports substances around the body.
(ROOT (S (NP (NP (DT The) (JJ main) (NN function)) (PP (IN of) (NP (DT the) (JJ circulatory) (NN system)))) (VP (VBZ is) (S (VP (TO to) (VP (VB transport) (NP (NNS materials)))))) (. .)))