( Energy ( ( is ( required ( for ( ( this type ) ( of transport ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Energy)) (VP (VBZ is) (VP (VBN required) (PP (IN for) (NP (NP (DT this) (NN type)) (PP (IN of) (NP (NN transport))))))) (. .)))
Energy is required for this type of transport .
(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)))))))))))) (. .)))