( ( ( ( Embryo sac ) , ) ( p 180 ) ) . )
(ROOT (NP (NP (NN Embryo) (NN sac)) (, ,) (NP (NN p) (CD 180)) (. .)))
Embryo sac, p 180.
(ROOT (S (NP (NP (DT The) (JJ amniotic) (NN sac)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBD was) (VP (VBG sitting) (PP (IN on) (NP (NP (NN top)) (PP (IN of) (NP (DT the) (JJ flat) (NN embryo))))))))) (, ,)) (VP (VBZ envelops) (NP (DT the) (NN embryo)) (SBAR (IN as) (S (NP (PRP it)) (VP (VBZ folds))))) (. .)))