( Elements ( ( heavier ( than iron ) ) ( ( are ( ( made ( in ( supernova explosions ) ) ) ( from ( ( the combination ) ( of ( ( the ( abundant neutrons ) ) ( with ( heavy nuclei ) ) ) ) ) ) ) ) . ) ) )
(ROOT (S (NP (NNS Elements)) (ADVP (ADVP (RBR heavier)) (PP (IN than) (NP (NN iron)))) (VP (VBP are) (VP (VBN made) (PP (IN in) (NP (NN supernova) (NNS explosions))) (PP (IN from) (NP (NP (DT the) (NN combination)) (PP (IN of) (NP (NP (DT the) (JJ abundant) (NNS neutrons)) (PP (IN with) (NP (JJ heavy) (NNS nuclei))))))))) (. .)))
Elements heavier than iron are made in supernova explosions from the combination of the abundant neutrons with heavy nuclei.
(ROOT (S (NP (NNS Supernovas)) (VP (VBP are) (ADJP (ADJP (NP (NP (DT the) (NN source)) (PP (IN of) (NP (NNS elements)))) (JJR heavier)) (PP (IN than) (NP (NN iron))))) (. .)))