( Obviously ( ( the development ) ( ( ( was not ) ( that ( of ( a ( 10 ( week fetus ) ) ) ) ) ) . ) ) )
(ROOT (S (ADVP (RB Obviously)) (NP (DT the) (NN development)) (VP (VBD was) (RB not) (NP (NP (DT that)) (PP (IN of) (NP (DT a) (CD 10) (NN week) (NN fetus))))) (. .)))
Obviously the development was not that of a 10 week fetus.
(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.