  The scattering of electrons on carbon, calcium, and argon targets are
analyzed using an approach that incorporates the contributions to the
electromagnetic response functions from the quasielastic (QE), inelastic
processes, and two-particle and two-hole meson exchange current ($2p-2h$ MEC).
This approach describes well the whole energy spectrum of data at very
different kinematics. It is shown that the accuracy of the $(e,e')$ cross
section calculations in the region between the QE and delta-resonance peaks,
where the $2p-2h$ MEC contribution reaches its maximum value, depends on the
momentum transfer $|\q|$ and at $|\q|>500$ MeV the calculated and measured
cross sections are in agreement within the experimental uncertainties.
