( ( ( Neutrons and ) protons ) ( each ( ( contain ( three quarks ) ) . ) ) )
(ROOT (S (NP (NNS Neutrons) (CC and) (NNS protons)) (DT each) (VP (VBP contain) (NP (CD three) (NNS quarks))) (. .)))
Neutrons and protons each contain three quarks.
(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))))) (. .)))