( ( ( Nitrogen gas ) ( in ( the atmosphere ) ) ) ( ( is ( composed ( of ( ( two ( nitrogen atoms ) ) ( bound ( to ( each other ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NN Nitrogen) (NN gas)) (PP (IN in) (NP (DT the) (NN atmosphere)))) (VP (VBZ is) (VP (VBN composed) (PP (IN of) (NP (NP (CD two) (NN nitrogen) (NNS atoms)) (VP (VBN bound) (PP (TO to) (NP (DT each) (JJ other)))))))) (. .)))
Nitrogen gas in the atmosphere is composed of two nitrogen atoms bound to each other.
(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))))) (. .)))