( ( ( The ( upper boundary ) ) ( of ( the mesosphere ) ) ) ( ( is ( ( ( the mesopause ) , ) ( which ( can ( ( be ( the coldest ) ) ( naturally ( ( ( occurring place ) ( on Earth ) ) ( with ( temperatures ( below ( 130 ( F C ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (JJ upper) (NN boundary)) (PP (IN of) (NP (DT the) (NN mesosphere)))) (VP (VBZ is) (NP (NP (DT the) (NN mesopause)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (MD can) (VP (VB be) (NP (DT the) (JJS coldest)) (S (ADVP (RB naturally)) (VP (VBG occurring) (NP (NN place)) (PP (IN on) (NP (NNP Earth))) (PP (IN with) (NP (NP (NNS temperatures)) (PP (IN below) (NP (CD 130) (NN F) (NNP C))))))))))))) (. .)))
The upper boundary of the mesosphere is the mesopause, which can be the coldest naturally occurring place on Earth with temperatures below 130 F C .
(ROOT (S (NP (DT The) (NN mesopause)) (VP (VBZ is) (PP (IN at) (NP (NP (DT the) (NN top)) (PP (IN of) (NP (DT the) (NN mesosphere)))))) (. .)))