( ( ( Atmospheric pressure ) ( at ( surface ( of earth ) ) ) ) ( ( is ( due ( to ( ( the weight ) ( of ( ( the air ) ( in ( our atmosphere ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (JJ Atmospheric) (NN pressure)) (PP (IN at) (NP (NP (NN surface)) (PP (IN of) (NP (NN earth)))))) (VP (VBZ is) (ADJP (JJ due) (PP (TO to) (NP (NP (DT the) (NN weight)) (PP (IN of) (NP (NP (DT the) (NN air)) (PP (IN in) (NP (PRP$ our) (NN atmosphere))))))))) (. .)))
Atmospheric pressure at surface of earth is due to the weight of the air in our atmosphere.
(ROOT (S (PP (IN At) (NP (NP (DT the) (NN earth) (POS 's)) (NN surface))) (, ,) (NP (NP (DT the) (NN air) (NN pressure)) (VP (VBN exerted) (PP (IN on) (NP (PRP you))))) (VP (VBZ is) (NP (NP (DT a) (NN result)) (PP (IN of) (NP (NP (DT the) (NN weight)) (PP (IN of) (NP (NP (NN air)) (PP (IN above) (NP (PRP you))))))))) (. .)))