( ( Sort ( of core ) ) ( ( features ( -LRB- ( ( like ( wings ( for birds ) ) ) -RRB- ) ) ) . ) )
(ROOT (S (NP (NP (NNP Sort)) (PP (IN of) (NP (NN core)))) (VP (VBZ features) (PRN (-LRB- -LRB-) (PP (IN like) (NP (NP (NNS wings)) (PP (IN for) (NP (NNS birds))))) (-RRB- -RRB-))) (. .)))
Sort of core features (like wings for birds).
(ROOT (S (NP (NP (DT The) (NN bird) (NN ancestor)) (SBAR (WHNP (WDT that)) (S (VP (VBD lived) (PP (IN in) (NP (NNS trees))))))) (VP (VBD developed) (NP (NP (NNS wings)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (ADVP (RB commonly)) (VP (VBN associated) (PP (IN with) (NP (NNS birds))))))))) (. .)))
The bird ancestor that lived in trees developed wings, which is commonly associated with birds.