( We ( ( ( ( ( studied ( ( cytochemical localization ) ( of ( ( ectoadenosine triphosphatase ) ( in ( the ( rat liver ) ) ) ) ) ) ) ( during development ) ) ( from ( 15-day-old fetus ) ) ) ( to ( 4-week-old ( and ( adult animal ) ) ) ) ) . ) )
(ROOT (S (NP (PRP We)) (VP (VBD studied) (NP (NP (JJ cytochemical) (NN localization)) (PP (IN of) (NP (NP (JJ ectoadenosine) (NN triphosphatase)) (PP (IN in) (NP (DT the) (NN rat) (NN liver)))))) (PP (IN during) (NP (NN development))) (PP (IN from) (NP (JJ 15-day-old) (NN fetus))) (PP (TO to) (NP (JJ 4-week-old) (CC and) (JJ adult) (NN animal)))) (. .)))
We studied cytochemical localization of ectoadenosine triphosphatase in the rat liver during development from 15-day-old fetus to 4-week-old and adult animal.
(ROOT (S (NP (NP (DT The) (NN development)) (PP (IN of) (NP (NP (DT the) (JJ respiratory) (NN system)) (PP (IN in) (NP (DT the) (NN fetus)))))) (VP (VBZ begins) (PP (IN at) (NP (QP (RB about) (CD 4)) (NNS weeks)))) (. .)))
The development of the respiratory system in the fetus begins at about 4 weeks.