( ( Water striders ) ( ( ( rely ( on ( surface tension ) ) ) ( to ( walk ( on ( top ( of water ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Water) (NNS striders)) (VP (VBP rely) (PP (IN on) (NP (NN surface) (NN tension))) (S (VP (TO to) (VP (VB walk) (PP (IN on) (NP (NP (NN top)) (PP (IN of) (NP (NN water))))))))) (. .)))
Water striders rely on surface tension to walk on top of water.
(ROOT (S (NP (JJ Surface) (NN tension)) (VP (VBZ is) (ADJP (JJ responsible) (PP (IN for) (NP (DT the) (NN fact)))) (SBAR (IN that) (S (NP (JJ small) (NNS insects)) (VP (MD can) (VP (VB walk) (PP (IN on) (NP (NN water)))))))) (. .)))