( ( In ( ( a process ) ( called ( nuclear fusion ) ) ) ) ( , ( ( ( the ( intense heat ) ) ( in ( the sun ) ) ) ( ( causes ( ( hydrogen atoms ) ( to ( ( ( break apart ) and ) ( ( fuse together ) ( to ( form ( helium atoms ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN In) (NP (NP (DT a) (NN process)) (VP (VBN called) (NP (JJ nuclear) (NN fusion))))) (, ,) (NP (NP (DT the) (JJ intense) (NN heat)) (PP (IN in) (NP (DT the) (NN sun)))) (VP (VBZ causes) (S (NP (NN hydrogen) (NNS atoms)) (VP (TO to) (VP (VP (VB break) (ADVP (RB apart))) (CC and) (VP (VB fuse) (PRT (RP together)) (S (VP (TO to) (VP (VB form) (NP (JJ helium) (NNS atoms)))))))))) (. .)))
In a process called nuclear fusion , the intense heat in the sun causes hydrogen atoms to break apart and fuse together to form helium atoms.
(ROOT (S (NP (NP (NNS Collisions)) (PP (IN between) (NP (NN hydrogen) (NNS atoms)))) (VP (VBP demonstrate) (NP (NP (CD one) (NN form)) (PP (IN of) (NP (JJ nuclear) (NN fusion))))) (. .)))