( ( ( ( ( BIOTIC ( INTERACTIONS DEFINITION ) ) ( The antagonistic ) ) and ) ( ( symbiotic interactions ) ( among organisms ) ) ) ( ( are ( some ( of ( ( the ( ( ( ( ( ( most important ) , ) but ) ( least understood ) ) , ) factors ) ) ( influencing ( ( the structure ) ( of ( natural ecosystems ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NP (NNP BIOTIC) (NNP INTERACTIONS) (NNP DEFINITION)) (NP (DT The) (JJ antagonistic))) (CC and) (NP (NP (JJ symbiotic) (NNS interactions)) (PP (IN among) (NP (NNS organisms))))) (VP (VBP are) (NP (NP (DT some)) (PP (IN of) (NP (NP (DT the) (ADJP (ADJP (RBS most) (JJ important)) (, ,) (CC but) (ADJP (RBS least) (JJ understood)) (, ,)) (NNS factors)) (VP (VBG influencing) (NP (NP (DT the) (NN structure)) (PP (IN of) (NP (JJ natural) (NNS ecosystems))))))))) (. .)))
BIOTIC INTERACTIONS DEFINITION The antagonistic and symbiotic interactions among organisms are some of the most important, but least understood, factors influencing the structure of natural ecosystems.
(ROOT (S (NP (NNP Community) (NNS interactions)) (VP (VBP are) (NP (NP (JJ important) (NNS factors)) (PP (IN in) (NP (JJ natural) (NN selection))))) (. .)))