As a mass of air rises it is exposed to decreasing atmospheric pressure and expands accordingly.
(a mass of air; rises; ) (it; is exposed; to decreasing atmospheric pressure; T:As a mass of air rises) (it; expands accordingly; T:As a mass of air rises)
a mass of air it it
rises is exposed expands accordingly
to decreasing atmospheric pressure T:As a mass of air rises
T:As a mass of air rises