( ( ( ( ( ( Much ( of ( the skull ) ) ) ( is ( formed ( from cartilage ) ) ) ) , ) and ) ( ( its ( overall structure ) ) ( is reduced ) ) ) . )
(ROOT (S (S (NP (NP (RB Much)) (PP (IN of) (NP (DT the) (NN skull)))) (VP (VBZ is) (VP (VBN formed) (PP (IN from) (NP (NN cartilage)))))) (, ,) (CC and) (S (NP (PRP$ its) (JJ overall) (NN structure)) (VP (VBZ is) (VP (VBN reduced)))) (. .)))
Much of the skull is formed from cartilage, and its overall structure is reduced.
(ROOT (S (NP (NNS Hagfishes)) (VP (VBP have) (NP (NP (DT a) (NN skull)) (VP (VBN made) (PP (IN of) (NP (NN cartilage)))))) (. .)))