( ( Vapor pressure ) ( ( ( decreases ( as ( salinity increases ) ) ) ( because ( ( salt ions ) ( reduce ( ( the evaporation ) ( of ( water molecules ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (JJ Vapor) (NN pressure)) (VP (VBZ decreases) (PP (IN as) (NP (JJ salinity) (NNS increases))) (SBAR (IN because) (S (NP (NN salt) (NNS ions)) (VP (VB reduce) (NP (NP (DT the) (NN evaporation)) (PP (IN of) (NP (NN water) (NNS molecules)))))))) (. .)))
Vapor pressure decreases as salinity increases because salt ions reduce the evaporation of water molecules.
(ROOT (S (S (VP (VBG Reducing) (NP (NP (DT the) (NN number)) (PP (IN of) (NP (NP (NNS molecules)) (PP (IN in) (NP (DT a) (JJ rigid) (NN container)))))))) (VP (VBZ causes) (NP (NN pressure)) (S (VP (TO to) (VP (VB decrease))))) (. .)))