( ( ( Nitrogen gas ) ( -LRB- ( N2 -RRB- ) ) ) ( ( ( ( ( is abundant ) ( on earth ) ) , ) ( ( making up ) ( ( ( about 75 ) percent ) ( of ( ( the ( planet 's ) ) atmosphere ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NN Nitrogen) (NN gas)) (PRN (-LRB- -LRB-) (NP (NNP N2)) (-RRB- -RRB-))) (VP (VBZ is) (ADJP (JJ abundant)) (PP (IN on) (NP (NN earth))) (, ,) (S (VP (VBG making) (PRT (RP up)) (NP (NP (QP (RB about) (CD 75)) (NN percent)) (PP (IN of) (NP (NP (DT the) (NN planet) (POS 's)) (NN atmosphere))))))) (. .)))
Nitrogen gas (N2) is abundant on earth, making up about 75 percent of the planet'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))))) (. .)))