( FUSION ( ( For ( ( the purpose ) ( of ( this class ) ) ) ) ( , ( ( is ( ( a ( nuclear reaction ) ) ( ( in which ) ( ( light nuclei ) ( combine ( to ( form ( ( a nucleus ) ( of ( a ( heavier ( mass number ) ) ) ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (ADVP (RB FUSION)) (PP (IN For) (NP (NP (DT the) (NN purpose)) (PP (IN of) (NP (DT this) (NN class))))) (, ,) (VP (VBZ is) (NP (NP (DT a) (JJ nuclear) (NN reaction)) (SBAR (WHPP (IN in) (WHNP (WDT which))) (S (NP (JJ light) (NNS nuclei)) (VP (VBP combine) (S (VP (TO to) (VP (VB form) (NP (NP (DT a) (NN nucleus)) (PP (IN of) (NP (DT a) (JJR heavier) (NN mass) (NN number)))))))))))) (. .)))
FUSION For the purpose of this class, is a nuclear reaction in which light nuclei combine to form a nucleus of a heavier mass number.
(ROOT (S (PP (IN In) (NP (DT the) (JJ nuclear) (NN fusion) (NN process))) (, ,) (NP (CD two) (JJ light) (NNS nuclei)) (VP (VBP combine) (S (VP (TO to) (VP (VB produce) (NP (NP (DT a) (JJR heavier) (NN nucleus)) (CC and) (NP (JJ great) (NN energy))))))) (. .)))