( ( ( ( ( Pressures ( in ( the Earth ) ) ) ( should ( increase ( the density ) ) ) ) and ) ( ( ( the heat ) ( in ( the Earth ) ) ) ( should ( decrease ( the density ) ) ) ) ) . )
(ROOT (S (S (NP (NP (NNS Pressures)) (PP (IN in) (NP (DT the) (NN Earth)))) (VP (MD should) (VP (VB increase) (NP (DT the) (NN density))))) (CC and) (S (NP (NP (DT the) (NN heat)) (PP (IN in) (NP (DT the) (NN Earth)))) (VP (MD should) (VP (VB decrease) (NP (DT the) (NN density))))) (. .)))
Pressures in the Earth should increase the density and the heat in the Earth should decrease the density.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NN gas) (NNS particles)) (VP (VB heat) (PRT (RP up))))) (, ,) (NP (NN pressure)) (VP (VBP increase)) (. .)))