( ( ( ( Volcanic Gases ) and ) Earth ) ( ( 's ( Atmosphere 37 ) ) . ) )
(ROOT (S (NP (NP (JJ Volcanic) (NNS Gases)) (CC and) (NP (NNP Earth))) (VP (VBZ 's) (NP (NNP Atmosphere) (CD 37))) (. .)))
Volcanic Gases and Earth's Atmosphere 37.
(ROOT (S (NP (JJ Volcanic) (NNS gases)) (VP (VBP helpe) (S (VP (TO to) (VP (VB form) (NP (DT the) (NN atmosphere)) (PP (IN on) (NP (NN earth))))))) (. .)))