( Scientists ( ( believe ( that ( ( ( protons and ) neutrons ) ( are ( ( ( ( made up ) ( of ( ( three particles ) ( known ( as quarks ) ) ) ) ) , ) ( along ( with ( ( the gluons ) ( that ( ( bind them ) together ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Scientists)) (VP (VBP believe) (SBAR (IN that) (S (NP (NNS protons) (CC and) (NNS neutrons)) (VP (VBP are) (VP (VBN made) (PRT (RP up)) (PP (IN of) (NP (NP (CD three) (NNS particles)) (VP (VBN known) (PP (IN as) (NP (NNS quarks)))))) (, ,) (PP (IN along) (IN with) (NP (NP (DT the) (NNS gluons)) (SBAR (WHNP (WDT that)) (S (VP (VBZ bind) (NP (PRP them)) (ADVP (RB together)))))))))))) (. .)))
Scientists believe that protons and neutrons are made up of three particles known as quarks, along with the gluons that bind them together.
(ROOT (S (NP (NP (DT The) (CD two) (JJ main) (JJ fundamental) (NNS particles)) (SBAR (WHNP (WDT that)) (S (VP (VBP make) (PRT (RP up)) (NP (NNS neutrons)))))) (VP (VBP are) (NP (NNS quarks) (CC and) (NNS gluons))) (. .)))