( ( The ( Nitrogen gas ) ) ( ( constitutes ( ( what percentage ) ( of ( ( the ( earth 's ) ) atmosphere ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NNP Nitrogen) (NN gas)) (VP (VBZ constitutes) (NP (NP (WP what) (NN percentage)) (PP (IN of) (NP (NP (DT the) (NN earth) (POS 's)) (NN atmosphere))))) (. .)))
The Nitrogen gas constitutes what percentage of the earth's atmosphere.
(ROOT (S (NP (NN Nitrogen) (NN gas)) (VP (VBZ comprises) (NP (NP (QP (RB about) (NNS three-fourths))) (PP (IN of) (NP (NP (NN earth) (POS 's)) (NN atmosphere))))) (. .)))