( However ( , ( ( even ( though ( they ( all ( affect ( ( the ( directed migration ) ) ( of ( the ( tracheal cells ) ) ) ) ) ) ) ) ) ( , ( they ( ( are ( active ( in ( ( different steps ) ( in ( ( the morphogenesis ) ( of ( the ( tracheal tree ) ) ) ) ) ) ) ) ) . ) ) ) ) ) )
(ROOT (S (ADVP (RB However)) (, ,) (SBAR (RB even) (IN though) (S (NP (PRP they)) (RB all) (VP (VB affect) (NP (NP (DT the) (JJ directed) (NN migration)) (PP (IN of) (NP (DT the) (JJ tracheal) (NNS cells))))))) (, ,) (NP (PRP they)) (VP (VBP are) (ADJP (JJ active) (PP (IN in) (NP (NP (JJ different) (NNS steps)) (PP (IN in) (NP (NP (DT the) (NNS morphogenesis)) (PP (IN of) (NP (DT the) (JJ tracheal) (NN tree))))))))) (. .)))
However, even though they all affect the directed migration of the tracheal cells, they are active in different steps in the morphogenesis of the tracheal tree.
(ROOT (S (NP (NNS Cells)) (VP (VB acquire) (NP (JJ different) (NNS identities)) (PP (IN in) (NP (NP (DT an) (JJ ordered) (JJ spatial) (NN arrangement)) (PP (IN during) (NP (NNS morphogenesis)))))) (. .)))