( ( ( ( ( ( Fish ( such ( as ( ( tuna and ) mackerel ) ) ) ) ( have ( ( a skeleton ) ( ( made ( of bone ) ) ( -LRB- ( ( just ( like humans ) ) -RRB- ) ) ) ) ) ) , ) but ) ( ( a ( shark skeleton ) ) ( is ( ( made entirely ) ( of ( cartilage ( -LRB- ( ( like ( human ( ( noses and ) ears ) ) ) -RRB- ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (NP (NN Fish)) (PP (JJ such) (IN as) (NP (NN tuna) (CC and) (NN mackerel)))) (VP (VBP have) (NP (NP (DT a) (NN skeleton)) (VP (VBN made) (PP (IN of) (NP (NN bone))) (PRN (-LRB- -LRB-) (PP (ADVP (RB just)) (IN like) (NP (NNS humans))) (-RRB- -RRB-)))))) (, ,) (CC but) (S (NP (DT a) (NN shark) (NN skeleton)) (VP (VBZ is) (VP (VBN made) (ADVP (RB entirely)) (PP (IN of) (NP (NP (NN cartilage)) (PRN (-LRB- -LRB-) (PP (IN like) (NP (JJ human) (NNS noses) (CC and) (NNS ears))) (-RRB- -RRB-))))))) (. .)))
Fish such as tuna and mackerel have a skeleton made of bone (just    like humans), but a shark skeleton is made entirely of cartilage (like    human noses and ears).
(ROOT (S (ADVP (RB Early) (PP (IN in) (NP (NP (DT the) (NN development)) (PP (IN of) (NP (DT a) (JJ human) (NN fetus)))))) (, ,) (NP (DT the) (NN skeleton)) (VP (VBZ is) (VP (VBN made) (ADVP (RB entirely)) (PP (IN of) (NP (NN cartilage))))) (. .)))