  The 2015 nuclear physics long-range plan endorsed the realization of an
Electron-Ion Collider (EIC) as the next large construction project after the
completion of FRIB. With its high luminosity ( $> 10^{33} cm^{-2}s^{-1}$), wide
kinematic reach in center-of-mass-energy (45GeV to 145GeV) and high lepton and
proton beam polarization, an EIC provides an unprecedented opportunity to reach
new frontiers in our understanding of the spin and dynamic structure of nuclei.
Despite of the success of the HERA collider in investigating the structure of a
single nucleon, the partonic structure of nuclei at moderate-to-small Bjorken's
$x$ still remains elusive. We present the evaluated impact of an EIC in
extracting the nuclear structure-functions from measurements of the reduced
cross section in deep inelastic scattering, including also the case of
measuring heavy quark production events. The potential constraints offered by
the EIC data in extracting the nuclear parton distribution functions is also
discussed.
