( ( ( ( ( which ( returns ( ( the distance ) ( between ( two positions ) ) ) ) ) , ) and ) ( ( ( ( the ( class FrogHopper ) ) and ) ( the ( struct Position ) ) ) ( defined below ) ) ) . )
(ROOT (S (S (NP (WDT which)) (VP (VBZ returns) (NP (NP (DT the) (NN distance)) (PP (IN between) (NP (CD two) (NNS positions)))))) (, ,) (CC and) (S (NP (NP (DT the) (NN class) (NN FrogHopper)) (CC and) (NP (DT the) (JJ struct) (NN Position))) (VP (VBD defined) (ADVP (RB below)))) (. .)))
which returns the distance between two positions, and the class FrogHopper and the struct Position defined below.
(ROOT (S (NP (NNP Distance)) (VP (VBZ is) (VP (VBN defined) (PP (IN as) (NP (NP (DT the) (NN magnitude) (CC or) (NN size)) (PP (IN of) (NP (NP (NN displacement)) (PP (IN between) (NP (CD two) (NNS positions))))))))) (. .)))