( ( Atmospheric pressure ) ( ( decreases ( with ( increasing altitude ) ) ) . ) )
(ROOT (S (NP (JJ Atmospheric) (NN pressure)) (VP (VBZ decreases) (PP (IN with) (NP (VBG increasing) (NN altitude)))) (. .)))
Atmospheric pressure 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))))))) (. .)))