( ( ( The pressure ) ( of ( the atmosphere ) ) ) ( ( decreases ( with ( increasing altitude ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN pressure)) (PP (IN of) (NP (DT the) (NN atmosphere)))) (VP (VBZ decreases) (PP (IN with) (NP (VBG increasing) (NN altitude)))) (. .)))
The pressure of the atmosphere decreases with increasing altitude.
(ROOT (S (NP (NNP Air)) (VP (VBP pressure) (SBAR (S (NP (PRP it)) (VP (VBZ decreases) (PP (IN as) (NP (NN altitude) (NNS increases))))))) (. .)))