( Diffusion ( ( is ( ( the process ) ( when ( particles ( ( move ( from ( areas ( of ( high concentration ) ) ) ) ) ( to ( areas ( of ( low concentration ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Diffusion)) (VP (VBZ is) (NP (NP (DT the) (NN process)) (SBAR (WHADVP (WRB when)) (S (NP (NNS particles)) (VP (VBP move) (PP (IN from) (NP (NP (NNS areas)) (PP (IN of) (NP (JJ high) (NN concentration))))) (PP (TO to) (NP (NP (NNS areas)) (PP (IN of) (NP (JJ low) (NN concentration)))))))))) (. .)))
Diffusion is the process when particles move from areas of high concentration to areas of low concentration.
(ROOT (S (NP (NNP Diffusion)) (VP (VBZ is) (NP (NP (DT the) (NN process)) (SBAR (WHPP (IN in) (WHNP (WDT which))) (S (NP (DT a) (NN substance)) (ADVP (RB naturally)) (VP (VBZ moves) (PP (IN from) (NP (NP (DT an) (NN area)) (PP (IN of) (NP (NP (JJR higher)) (PP (TO to) (NP (JJR lower) (NN concentration)))))))))))) (. .)))
Diffusion is the process in which a substance naturally moves from an area of higher to lower concentration.