( ( ( STRATOSPHERE -- ) ( Part ( of ( ( ( the atmosphere ) , ) ( ( the gases ) ( that ( encircle ( the Earth ) ) ) ) ) ) ) ) . )
(ROOT (NP (NP (NNP STRATOSPHERE)) (: --) (NP (NP (NN Part)) (PP (IN of) (NP (NP (DT the) (NN atmosphere)) (, ,) (NP (NP (DT the) (NNS gases)) (SBAR (WHNP (WDT that)) (S (VP (VBP encircle) (NP (DT the) (NN Earth))))))))) (. .)))
STRATOSPHERE -- Part of the atmosphere, the gases that encircle the Earth.
(ROOT (S (NP (DT The) (NN stratosphere)) (VP (VBZ is) (NP (DT the) (NN heat) (NN source))) (. .)))