( ( ( Venus ' ) atmosphere ) ( ( ( is primarily ) ( ( ( ( carbon dioxide ) , ) and ) ( ( much thicker ) ( than ( ( the atmosphere ) ( on Earth ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNP Venus) (POS ')) (NN atmosphere)) (VP (VBZ is) (ADVP (RB primarily)) (NP (NP (NN carbon) (NN dioxide)) (, ,) (CC and) (NP (NP (RB much) (JJR thicker)) (PP (IN than) (NP (NP (DT the) (NN atmosphere)) (PP (IN on) (NP (NNP Earth)))))))) (. .)))
Venus' atmosphere is primarily carbon dioxide, and much thicker than the atmosphere on Earth.
(ROOT (S (PP (IN During) (NP (DT the) (JJ early) (NN paleozoic))) (, ,) (NP (NP (DT the) (NN amount)) (PP (IN of) (NP (NP (NN carbon) (NN dioxide)) (PP (IN in) (NP (DT the) (NN atmosphere)))))) (VP (VBD was) (ADJP (RB much) (JJR greater)) (PP (VBN compared) (PP (TO to) (NP (NN today))))) (. .)))