( Saturn ( ( has ( ( a ( thick atmosphere ) ) ( ( made up ) ( of ( ( ( mostly hydrogen ) and ) helium ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Saturn)) (VP (VBZ has) (NP (NP (DT a) (JJ thick) (NN atmosphere)) (VP (VBN made) (PRT (RP up)) (PP (IN of) (NP (NP (RB mostly) (NN hydrogen)) (CC and) (NP (NNP helium))))))) (. .)))
Saturn has a thick atmosphere made up of 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))))) (. .)))