( Dispersion ( ( is ( controlled ( ( ( by ( ( ( diffusion , ) ( which ( is ( ( the movement ) ( from ( areas ( of ( ( high ( to low ) ) concentrations ) ) ) ) ) ) ) ) , ) ) and ) ( by ( ( mixing , ) ( which ( is ( ( the movement ) ( of ( air ( in ( the space ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Dispersion)) (VP (VBZ is) (VP (VBN controlled) (PP (PP (IN by) (NP (NP (NN diffusion)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (NP (NP (DT the) (NN movement)) (PP (IN from) (NP (NP (NNS areas)) (PP (IN of) (NP (ADJP (JJ high) (TO to) (JJ low)) (NNS concentrations))))))))) (, ,))) (CC and) (PP (IN by) (NP (NP (NNP mixing)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (NP (NP (DT the) (NN movement)) (PP (IN of) (NP (NP (NN air)) (PP (IN in) (NP (DT the) (NN space)))))))))))))) (. .)))
Dispersion is controlled by diffusion, which is the movement from areas of high to low concentrations, and by mixing, which is the movement of air in the space.
(ROOT (S (NP (PRP You)) (VP (VBP call) (NP (NP (DT the) (NN movement)) (PP (IN of) (NP (DT a) (NN substance)))) (PP (IN from) (NP (NP (DT an) (NN area)) (PP (IN of) (NP (NP (DT a) (JJR higher) (NN amount)) (PP (IN toward) (NP (NP (DT an) (NN area)) (PP (IN of) (NP (JJR lower) (NN amount) (NN diffusion)))))))))) (. .)))