Critical Tests of QCD at the EIC

Nuclear Physics community recommended a high-energy high-luminosity polarized EIC as the highest priority for new facility construction following the completion of FRIB in its 2015 Long-Range Plan. National Academy of Sciences provided ``An Assessment of U.S.-Based Electron-Ion Collider Science'' in 2018, finding the science that EIC will achieve is unique and world leading and will ensure global U.S. leadership in nuclear science, as well as in accelerator science and the technology of colliders. In this talk, I will briefly review specific measurements at the EIC that provide critical tests of our understanding of mass, spin, hadron structure, and emergent properties of dense systems in QCD.