( ( Air ( ( pressure and ) density ) ) ( ( continue ( to ( decrease ( as ( ( ( ( altitude increases ) and ) ( the atmosphere ) ) ( dwindles ( into ( ( the ( near vacuum ) ) ( of space ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Air) (NN pressure) (CC and) (NN density)) (VP (VBP continue) (S (VP (TO to) (VP (VB decrease) (SBAR (IN as) (S (NP (NP (NN altitude) (NNS increases)) (CC and) (NP (DT the) (NN atmosphere))) (VP (VBZ dwindles) (PP (IN into) (NP (NP (DT the) (JJ near) (NN vacuum)) (PP (IN of) (NP (NN space)))))))))))) (. .)))
Air pressure and density continue to decrease as altitude  increases and the atmosphere dwindles into the near vacuum of space.
(ROOT (S (NP (NNP Air)) (VP (VBP pressure) (SBAR (S (NP (PRP it)) (VP (VBZ decreases) (PP (IN as) (NP (NN altitude) (NNS increases))))))) (. .)))