( ( ( The ( decay rate ) ) ( of ( each ( radioactive isotope ) ) ) ) ( ( is ( stated ( in ( terms ( of ( ( ( its half-life ) , ) ( which ( ( is ( ( the time ) ( in years ) ) ) ( that ( it ( ( takes ( for ( one-half ( of ( ( the ( original parent ) ) ( to decay ) ) ) ) ) ) ( into ( the daughter ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN decay) (NN rate)) (PP (IN of) (NP (DT each) (JJ radioactive) (NN isotope)))) (VP (VBZ is) (VP (VBN stated) (PP (IN in) (NP (NP (NNS terms)) (PP (IN of) (NP (NP (PRP$ its) (NN half-life)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (NP (NP (DT the) (NN time)) (PP (IN in) (NP (NNS years)))) (SBAR (IN that) (S (NP (PRP it)) (VP (VBZ takes) (PP (IN for) (NP (NP (NN one-half)) (PP (IN of) (NP (NP (DT the) (JJ original) (NN parent)) (PP (TO to) (NP (NN decay))))))) (PP (IN into) (NP (DT the) (NN daughter))))))))))))))) (. .)))
The decay rate of each radioactive isotope is stated in terms of its half-life , which is the time in years that it takes for one-half of the original parent to decay into the daughter .
(ROOT (S (NP (DT The) (NN decay) (NN rate)) (VP (VBZ is) (VP (VBN measured) (PP (IN in) (NP (NP (DT a) (NN unit)) (VP (VBN called) (NP (DT the) (NN half-life))))))) (. .)))