( Diffusion ( ( is ( where ( elements ( ( move ( from ( ( an area ) ( of ( high concentration ) ) ) ) ) ( to ( ( an area ) ( of ( low concentration ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Diffusion)) (VP (VBZ is) (SBAR (WHADVP (WRB where)) (S (NP (NNS elements)) (VP (VBP move) (PP (IN from) (NP (NP (DT an) (NN area)) (PP (IN of) (NP (JJ high) (NN concentration))))) (PP (TO to) (NP (NP (DT an) (NN area)) (PP (IN of) (NP (JJ low) (NN concentration))))))))) (. .)))
Diffusion is      where elements move from an area of high concentration to an      area of low concentration.
(ROOT (S (NP (NNP Diffusion)) (VP (VBZ is) (NP (NP (DT the) (NN term)) (PP (IN for) (NP (NP (DT the) (NN movement)) (PP (IN of) (NP (NP (NNS molecules)) (PP (IN from) (NP (NP (DT an) (NN area)) (PP (IN of) (NP (NP (JJ high) (NN concentration)) (PP (TO to) (NP (NP (DT an) (NN area)) (PP (IN of) (NP (JJ low) (NN concentration))))))))))))))) (. .)))