( ( Heart ( Valves ( Heart valves ) ) ) ( ( ( ( are ( very important ) ) , ) ( as ( they ( prevent ( ( the backflow ) ( of ( ( blood , ) ( which ( ( ensures ( ( the ( proper direction ) ) ( of ( blood flow ) ) ) ) ( through ( the ( circulatory system ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Heart) (NNP Valves) (NNP Heart) (NNS valves)) (VP (VBP are) (ADJP (RB very) (JJ important)) (, ,) (SBAR (IN as) (S (NP (PRP they)) (VP (VBP prevent) (NP (NP (DT the) (NN backflow)) (PP (IN of) (NP (NP (NN blood)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ ensures) (NP (NP (DT the) (JJ proper) (NN direction)) (PP (IN of) (NP (NN blood) (NN flow)))) (PP (IN through) (NP (DT the) (JJ circulatory) (NN system))))))))))))) (. .)))
Heart Valves Heart valves are very important, as they prevent the backflow of blood, which ensures the proper direction of blood flow through the circulatory system.
(ROOT (S (NP (NNP Heart) (NNS valves)) (VP (VBP prevent) (NP (NP (DT the) (NN backflow)) (PP (IN of) (NP (NN blood)))) (PP (IN from) (S (VP (VBG happening) (PP (IN in) (NP (DT the) (NN heart))))))) (. .)))