( ( ( ( ( ( ( ( Collagen fibrils ) ( -LRB- ( 5 -RRB- ) ) ) , ) ( ( a ( zonula occludens ) ) ( -LRB- ( 7 -RRB- ) ) ) ) and ) ( ( the lumen ) ( of ( the ( lung alveolus ) ) ) ) ) ( -LRB- ( 8 -RRB- ) ) ) ( ( ( can also ) ( be observed ) ) . ) )
(ROOT (S (NP (NP (NP (NP (NNP Collagen) (NNS fibrils)) (PRN (-LRB- -LRB-) (NP (CD 5)) (-RRB- -RRB-))) (, ,) (NP (NP (DT a) (NN zonula) (NNS occludens)) (PRN (-LRB- -LRB-) (NP (CD 7)) (-RRB- -RRB-))) (CC and) (NP (NP (DT the) (NN lumen)) (PP (IN of) (NP (DT the) (NN lung) (NNS alveolus))))) (PRN (-LRB- -LRB-) (NP (CD 8)) (-RRB- -RRB-))) (VP (MD can) (ADVP (RB also)) (VP (VB be) (ADJP (JJ observed)))) (. .)))
Collagen  fibrils (5), a zonula occludens (7) and the lumen of the lung alveolus (8) can also be observed.
(ROOT (S (NP (NP (DT The) (NNS lungs)) (PP (IN of) (NP (NNS mammals)))) (VP (VBP are) (ADJP (JJ unique) (PP (IN in) (S (VP (VBG having) (NP (NNS alveoli))))))) (. .)))