Which of the following contribute(s) to most of the mass of an atom? O A) Protons and electrons
B) Protons only
C) Protons and neutrons
OD) Neutrons only

Americium-241 undergoes fission to produce three neutrons per fission event. if a neutron-absorbing material is mixed in with this sample so that the rate of neutron production drops down to 1.8 neutrons per fission event, which will be effective at achieving a critical mass? check all that apply. remove a deflective shield surrounding the sample. remove absorbent material mixed in with the sample. compress the sample of americium-241.