( Epithelia ( ( ( allow and ) ( ( ( regulate ( ( the passage ) ( of ( materials ( -LRB- ( ( ( ( ( diffusion , ) absorption ) , ) ( filtration ( , ( secretion ( , excretion ) ) ) ) ) -RRB- ) ) ) ) ) ) ( ( ( into and ) out ) ( of ( ( the ( deeper tissues ) ) ( of ( the body ) ) ) ) ) ) ( which ( they ( ( cover or ) line ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Epithelia)) (VP (VP (VB allow)) (CC and) (VP (VB regulate) (NP (NP (DT the) (NN passage)) (PP (IN of) (NP (NP (NNS materials)) (PRN (-LRB- -LRB-) (NP (NN diffusion)) (, ,) (NP (NN absorption)) (, ,) (NP (NN filtration) (, ,) (NN secretion) (, ,) (NN excretion)) (-RRB- -RRB-))))) (PP (IN into) (CC and) (IN out) (PP (IN of) (NP (NP (DT the) (JJR deeper) (NNS tissues)) (PP (IN of) (NP (DT the) (NN body)))))) (SBAR (WHNP (WDT which)) (S (NP (PRP they)) (VP (VB cover) (CC or) (VB line)))))) (. .)))
Epithelia allow and regulate the passage of materials (diffusion, absorption, filtration, secretion, excretion) into and out of the deeper tissues of the body which they cover or line.
(ROOT (S (NP (NP (DT The) (JJ main) (NNS functions)) (PP (IN of) (NP (NN epithelia)))) (VP (VBP are) (NP (NP (NN protection)) (PP (IN from) (NP (NP (DT the) (NN environment) (, ,) (NN coverage) (, ,) (NN secretion) (CC and) (NN excretion)) (, ,) (NP (NN absorption)) (, ,) (CC and) (NP (NN filtration)))))) (. .)))