( They ( ( are ( ( ( ( ( ( ( ( the troposphere ) , ) stratosphere ) , ) mesosphere ) , ) and ) ( the thermosphere ) ) ) . ) )
(ROOT (S (NP (PRP They)) (VP (VBP are) (NP (NP (DT the) (NNP troposphere)) (, ,) (NP (NN stratosphere)) (, ,) (NP (NN mesosphere)) (, ,) (CC and) (NP (DT the) (NN thermosphere)))) (. .)))
They are the troposphere, stratosphere, mesosphere, and the thermosphere.
(ROOT (S (NP (DT The) (NN stratosphere)) (VP (VBZ is) (NP (NP (DT the) (NN layer)) (PP (IN above) (NP (DT the) (NNP troposphere))))) (. .)))