( ( ( A ( heavy ( radioactive isotope ) ) ) ( of ( carbon ( of ( mass ( number 14 ) ) ) ) ) ) ( ( ( used especially ) ( ( ( in ( tracer studies ) ) and ) ( in ( dating ( archaeological ( and ( geological materials ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT A) (JJ heavy) (NN radioactive) (NN isotope)) (PP (IN of) (NP (NP (NN carbon)) (PP (IN of) (NP (NN mass) (NN number) (CD 14)))))) (VP (VBD used) (ADVP (RB especially)) (PP (PP (IN in) (NP (NN tracer) (NNS studies))) (CC and) (PP (IN in) (S (VP (VBG dating) (NP (JJ archaeological) (CC and) (JJ geological) (NNS materials))))))) (. .)))
A heavy radioactive isotope of carbon of mass number 14 used especially in tracer studies and in dating archaeological and geological materials.
(ROOT (S (NP (NP (NNP Carbon) (CD 14) (NN isotope)) (PP (IN of) (NP (NN carbon)))) (VP (VBZ is) (ADVP (RB typically)) (VP (VBN used) (PP (TO to) (NP (NN date) (JJ ancient) (NNS items))))) (. .)))