  We present measurements of the neutrino and antineutrino total
charged-current cross sections on carbon and their ratio using the MINERvA
scintillator-tracker. The measurements span the energy range 2-22 GeV and were
performed using forward and reversed horn focusing modes of the Fermilab
low-energy NuMI beam to obtain large neutrino and antineutrino samples. The
flux is obtained using a sub-sample of charged-current events at low hadronic
energy transfer along with precise higher energy external neutrino cross
section data overlapping with our energy range between 12-22 GeV. We also
report on the antineutrino-neutrino cross section ratio, Rcc, which does not
rely on external normalization information. Our ratio measurement, obtained
within the same experiment using the same technique, benefits from the
cancellation of common sample systematic uncertainties and reaches a precision
of 5% at low energy. Our results for the antineutrino-nucleus scattering cross
section and for Rcc are the most precise to date in the energy range $E_{\nu}
<$ 6GeV.
