( ( ( ( ( ( Because ( ( the ribs ) ( are ( still ( cartilaginous ( -LRB- ( ( instead ( of bony ) ) -RRB- ) ) ) ) ) ) ) ( , ( they bend ) ) ) , ) and ) ( ( rib ( cage volume ) ) ( actually decreases ) ) ) . )
(ROOT (S (S (SBAR (IN Because) (S (NP (DT the) (NNS ribs)) (VP (VBP are) (ADJP (ADVP (RB still)) (JJ cartilaginous) (PRN (-LRB- -LRB-) (PP (RB instead) (IN of) (NP (NN bony))) (-RRB- -RRB-)))))) (, ,) (NP (PRP they)) (VP (VB bend))) (, ,) (CC and) (S (NP (NN rib) (NN cage) (NN volume)) (ADVP (RB actually)) (VP (VBZ decreases))) (. .)))
Because the ribs are still cartilaginous (instead of bony), they bend, and rib cage volume actually decreases.
(ROOT (S (NP (JJS Most) (NN turtle) (NNS bodies)) (VP (VBP are) (VP (VBN covered) (PP (IN by) (NP (NP (DT a) (JJ special) (NN bony) (CC or) (NNS cartilaginous) (NN shell)) (VP (VBN developed) (PP (IN from) (NP (PRP$ their) (NNS ribs)))))))) (. .)))