( ( ( Star ( Birth Stars ) ) ( are ( born ( when ( ( clouds ( of ( ( dust ( and ( gas collapse ) ) ) ( because ( of gravity ) ) ) ) ) ( ( As ( ( ( more and ) more ) material ) ) ( falls ( onto ( the ( forming star ) ) ) ) ) ) ) ) ) ) ( , ( it ( finally ( ( ( becomes ( hot ( and ( dense enough ) ) ) ) ( at ( its ( center ( to ( trigger ( ( the ( nuclear ( fusion reactions ) ) ) ( that ( make ( ( ( ( stars , ) ( including ( our Sun ) ) ) , ) shine ) ) ) ) ) ) ) ) ) ) . ) ) ) ) )
(ROOT (S (S (NP (NNP Star) (NNP Birth) (NNP Stars)) (VP (VBP are) (VP (VBN born) (SBAR (WHADVP (WRB when)) (S (NP (NP (NNS clouds)) (PP (IN of) (NP (NP (NN dust) (CC and) (NN gas) (NN collapse)) (PP (RB because) (IN of) (NP (NN gravity)))))) (PP (IN As) (NP (ADJP (JJR more) (CC and) (JJR more)) (NN material))) (VP (VBZ falls) (PP (IN onto) (NP (DT the) (JJ forming) (NN star))))))))) (, ,) (NP (PRP it)) (ADVP (RB finally)) (VP (VBZ becomes) (NP (JJ hot) (CC and) (JJ dense) (NN enough)) (PP (IN at) (NP (PRP$ its) (NN center) (S (VP (TO to) (VP (VB trigger) (NP (NP (DT the) (JJ nuclear) (NN fusion) (NNS reactions)) (SBAR (WHNP (WDT that)) (S (VP (VBP make) (SBAR (S (NP (NP (NNS stars)) (, ,) (PP (VBG including) (NP (PRP$ our) (NN Sun))) (, ,)) (VP (VBP shine)))))))))))))) (. .)))
Star Birth Stars are born when clouds of dust and gas collapse because of gravity As more and more material falls onto the forming star, it finally becomes hot and dense enough at its center to trigger the nuclear fusion reactions that make stars, including our Sun, shine.
(ROOT (S (NP (NP (JJ Nuclear) (NN fusion)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ results) (PP (RB because) (IN of) (NP (NP (JJ great) (NN pressure)) (PP (IN at) (NP (NP (DT the) (NN center)) (PP (IN of) (NP (DT a) (NN star)))))))))) (, ,)) (VP (VBZ causes) (S (NP (NNS stars)) (VP (TO to) (VP (VB shine))))) (. .)))