Question

what does the atomic mass unit represent? *

the mass of one proton or neutron, approximately

the charge of an electron

the number of protons in an atom

the volume of an atom

Explanation:

The atomic mass unit (amu) is a unit of mass used to express atomic and molecular weights. Protons and neutrons have masses close to 1 amu. The charge of an electron is a measure of electric charge (not mass). The number of protons in an atom is the atomic number. The volume of an atom is a measure of space (not mass).

Answer:

The mass of one proton or neutron, approximately.