( ( ( Protons and ) neutrons ) ( ( are ( composed ( of ( ( three quarks ) each ) ) ) ) . ) )
(ROOT (S (NP (NNS Protons) (CC and) (NNS neutrons)) (VP (VBP are) (VP (VBN composed) (PP (IN of) (NP (NP (CD three) (NNS quarks)) (NP (DT each)))))) (. .)))
Protons and neutrons are composed of three quarks each.
(ROOT (S (NP (EX There)) (VP (VBP are) (NP (NP (CD three) (NNS quarks)) (PP (IN in) (NP (DT each) (NN proton) (CC and) (NN neutron))))) (. .)))