( ( In ( passive transport ) ) ( ( a substance ) ( ( ( moves ( from ( ( a region ) ( of ( high concentration ) ) ) ) ) ( to ( one ( of ( lower concentration ) ) ) ) ) . ) ) )
(ROOT (S (PP (IN In) (NP (JJ passive) (NN transport))) (NP (DT a) (NN substance)) (VP (VBZ moves) (PP (IN from) (NP (NP (DT a) (NN region)) (PP (IN of) (NP (JJ high) (NN concentration))))) (PP (TO to) (NP (NP (CD one)) (PP (IN of) (NP (JJR lower) (NN concentration)))))) (. .)))
In passive transport a substance moves from a region of high concentration to one of lower concentration.
(ROOT (S (NP (NNP Passive) (NN transport)) (VP (VP (VBZ requires) (NP (DT no) (NN energy))) (CC and) (VP (VBZ occurs) (SBAR (WHADVP (WRB when)) (S (NP (NNS substances)) (VP (VBP move) (PP (IN from) (NP (NP (NNS areas)) (PP (IN of) (NP (NP (JJR higher)) (PP (TO to) (NP (JJR lower) (NN concentration)))))))))))) (. .)))