( and ( ( ( the essence ) ( of ( the ( atomic nucleus ) ) ) ) ( ( are ( the ( ( protons and ) neutrons ) ) ) . ) ) )
(ROOT (S (CC and) (NP (NP (DT the) (NN essence)) (PP (IN of) (NP (DT the) (JJ atomic) (NN nucleus)))) (VP (VBP are) (NP (DT the) (NNS protons) (CC and) (NNS neutrons))) (. .)))
and the essence of the atomic nucleus are the protons and neutrons.
(ROOT (S (NP (NNS Protons) (CC and) (NNS neutrons)) (VP (VBP are) (VP (VBN located) (PP (IN in) (NP (DT the) (JJ central) (NN nucleus))))) (. .)))