( ( For example ) ( , ( ( ( a ( frog 's ) ) heart ) ( ( has ( ( three chambers ) ( instead ( of four ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN For) (NP (NN example))) (, ,) (NP (NP (DT a) (NN frog) (POS 's)) (NN heart)) (VP (VBZ has) (NP (NP (CD three) (NNS chambers)) (PP (RB instead) (IN of) (NP (CD four))))) (. .)))
For example, a frog's heart has three chambers instead of four.
(ROOT (S (PP (IN Like) (NP (NP (DT all) (NNS tetrapods)) (PP (IN except) (NP (NNS birds) (CC and) (NNS mammals))))) (, ,) (NP (NNS frogs)) (VP (VBP possess) (NP (NP (DT a) (NN heart)) (PP (IN with) (NP (CD three) (NNS chambers))))) (. .)))