( ( Nuclear energy ) ( ( is ( released ( by ( ( the splitting ) ( of ( ( the nucleus ) ( of ( an atom ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (JJ Nuclear) (NN energy)) (VP (VBZ is) (VP (VBN released) (PP (IN by) (NP (NP (DT the) (NN splitting)) (PP (IN of) (NP (NP (DT the) (NN nucleus)) (PP (IN of) (NP (DT an) (NN atom))))))))) (. .)))
Nuclear energy is released by the splitting of the nucleus of an atom.
(ROOT (S (NP (JJ Nuclear) (NN energy)) (VP (VBZ is) (VP (VBN released) (SBAR (WHADVP (WRB when)) (S (NP (NP (DT the) (NN nucleus)) (PP (IN of) (NP (DT an) (NN atom)))) (VP (VBZ is) (VP (VBN split))))))) (. .)))