( ( ( ( ( Protein ( acts ( like ( a sponge ) ) ) ) , ) and ) ( ( as ( it ( decreases ( in ( the body ) ) ) ) ) ( , ( ( osmotic pressure ) ( ( decreases , ) ( ( causing water ) ( to ( be ( ( ( absorbed and ) retained ) ( in ( protein molecules ) ) ) ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (NNP Protein)) (VP (VBZ acts) (PP (IN like) (NP (DT a) (NN sponge))))) (, ,) (CC and) (S (SBAR (IN as) (S (NP (PRP it)) (VP (VBZ decreases) (PP (IN in) (NP (DT the) (NN body)))))) (, ,) (NP (JJ osmotic) (NN pressure)) (VP (VBZ decreases) (, ,) (S (VP (VBG causing) (NP (NN water)) (S (VP (TO to) (VP (VB be) (VP (VBN absorbed) (CC and) (VBN retained) (PP (IN in) (NP (NN protein) (NNS molecules))))))))))) (. .)))
Protein acts like a sponge, and as it decreases  in the body, osmotic pressure decreases, causing water to be absorbed and retained in protein 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))))) (. .)))