( ( Another ( basic difference ) ) ( ( is ( that ( ( all mammals ) ( ( have ( ( three bones ) ( in ( their ( middle ear ) ) ) ) ) ( -LRB- ( ( ( ( ( ( hammer , ) anvil ) , ) and ) stirrup ) -RRB- ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT Another) (JJ basic) (NN difference)) (VP (VBZ is) (SBAR (IN that) (S (NP (DT all) (NNS mammals)) (VP (VBP have) (NP (NP (CD three) (NNS bones)) (PP (IN in) (NP (PRP$ their) (JJ middle) (NN ear)))) (PRN (-LRB- -LRB-) (NP (NP (NNP hammer)) (, ,) (NP (NN anvil)) (, ,) (CC and) (NP (NN stirrup))) (-RRB- -RRB-)))))) (. .)))
Another basic difference is that all mammals have three bones in their middle ear (hammer, anvil, and stirrup).
(ROOT (S (NP (DT The) (JJ mammalian) (JJ middle) (NN ear)) (VP (VBZ has) (NP (CD three) (NNS bones))) (. .)))