Multiple choice The atom's nucleus is held together by which of the following: strong interactions of the lepton and gluon constituents of the atom's nucleus weak interactions of the quark and lepton constituents of the atom's nucleus strong interactions of the quark and lepton constituents of the atom's nucleus strong interactions of the quark and gluon constituents of the atom's nucleus Reveal answer Fill a bubble to check yourself D Correct answer Explanation The atomic nucleus is held together by the strong nuclear force, which acts between quarks mediated by gluons.