( Saturn ( ( is ( almost ( identical ( to ( ( ( ( ( ( ( Jupiter ( in ( overall structure ) ) ) -- ) ( ( a ( giant globe ) ) ( of gas ) ) ) , ) ( mostly hydrogen ) ) and ) helium ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Saturn)) (VP (VBZ is) (ADJP (RB almost) (JJ identical) (PP (TO to) (NP (NP (NP (NP (NNP Jupiter)) (PP (IN in) (NP (JJ overall) (NN structure)))) (: --) (NP (NP (DT a) (JJ giant) (NN globe)) (PP (IN of) (NP (NN gas))))) (, ,) (NP (RB mostly) (NN hydrogen)) (CC and) (NP (NNP helium)))))) (. .)))
Saturn is almost identical to Jupiter in overall structure -- a giant globe of gas, mostly hydrogen and helium.
(ROOT (S (NP (NNP Saturn)) (VP (VBZ is) (VP (VBN made) (ADVP (RB mostly)) (PP (IN of) (NP (NN helium) (CC and) (NN hydrogen))))) (. .)))