( ( ( ( ( The ( smooth flagellum ) ) , ) ( angled posteriorly ) ) , ) ( ( ( ( ( ( ( ( is shorter ) , ) and ) ( attaches ( to ( substrates ( in ( non-motile cells ) ) ) ) ) ) , ) but ) ( ( trails behind ) ( in ( motile cells ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (JJ smooth) (NN flagellum)) (, ,) (VP (VBN angled) (ADVP (RB posteriorly))) (, ,)) (VP (VP (VBZ is) (ADJP (JJR shorter))) (, ,) (CC and) (VP (VBZ attaches) (PP (TO to) (NP (NP (NNS substrates)) (PP (IN in) (NP (JJ non-motile) (NNS cells)))))) (, ,) (CC but) (VP (VBZ trails) (PRT (RP behind)) (PP (IN in) (NP (JJ motile) (NNS cells))))) (. .)))
The smooth flagellum, angled posteriorly, is shorter, and attaches to substrates in non-motile cells, but trails behind in motile cells.
(ROOT (S (PP (IN In) (NP (NNS humans))) (, ,) (NP (DT the) (NN sperm) (NN cell)) (VP (VBZ is) (NP (NP (DT the) (JJ only) (NN cell)) (PP (IN with) (NP (DT the) (NN flagella) (NN structure))) (SBAR (WHNP (WDT that)) (S (VP (VBZ enables) (ADVP (RB motility))))))) (. .)))