Final answer:
Scientists use the atomic mass unit (amu) to measure the mass of individual atoms. One amu is equal to one-twelfth the mass of an atom of carbon-12. This unit allows for easy comparison of different atom masses.
Step-by-step explanation:
Scientists use the atomic mass unit (amu) to measure the mass of individual atoms. One amu is defined as one-twelfth the mass of an atom of carbon-12. This unit allows scientists to compare the masses of different atoms more easily. For example, an atom of helium-4 has a mass of 4.0026 amu, while an atom of sulfur-32 has a mass of 31.972 amu.