Answer is: (4) proton and neutron.
One unified atomic mass unit is approximately the mass of one nucleon (proton or neutron).
The unified atomic mass unit (amu) is a standard unit of atom mass.
One unified atomic mass unit is approximately the mass of one nucleon (1.66·10⁻²⁷ kg).
For example, one carbon atom has mass of 12 amu (unified atomic mass).
The electron has a mass that is approximately 1/1836 that of the proton.
Answer:
they board up the windows evacuate sometimes and barricade doors
Explanation:
