Final answer:
Electrons have a negative charge and constitute most of the mass of an atom, while neutrons have no charge and contribute significantly to the mass of an atom.
Step-by-step explanation:
Electrons have a negative charge and constitute most of the mass of an atom. Neutrons have no charge and contribute significantly to the mass of an atom. Protons and neutrons, which are located in the nucleus, have approximately the same mass, while electrons have a much smaller mass. Therefore, the correct answer is that more than one of the above answers are correct.