What sub-atomic particles make up the majority of the atomic mass (amu) of an atom? b
protons & neutrons
electrons & protons
neutrons & electrons
С

b. protons and neutrons

Explanation:

neutrons and protons constitute almost all of an atom's mass. The third type of stable particle is the electrons. Electrons have a negative charge but are extremely small and have a mass only 1/1850 that of a proton or neutron. They are so small that for practical purposes they do not contribute to the mass of the atom.