( ( ( Mass defects ) ( in ( atomic masses ) ) ) . )
(ROOT (NP (NP (NNP Mass) (NNS defects)) (PP (IN in) (NP (JJ atomic) (NNS masses))) (. .)))
Mass defects in atomic masses.
(ROOT (S (NP (NP (DT The) (NN sum)) (PP (IN of) (NP (NP (DT the) (NNS masses)) (PP (IN of) (NP (NP (DT the) (NNS atoms)) (PP (IN in) (NP (DT the) (NN formula)))))))) (VP (VBZ is) (VP (VBN referred) (PP (TO to) (NP (RB as) (JJ molecular) (NN mass))))) (. .)))