  Resonant inelastic light scattering experiments access the low lying
excitations of electron liquids in the fractional quantum Hall regime in the
range $2/5 \geq \nu \geq 1/3$. Modes associated with changes in the charge and
spin degrees of freedom are measured. Spectra of spin reversed excitations at
filling factor $\nu \gtrsim 1/3$ and at $\nu \lesssim 2/5$ identify a structure
of lowest spin-split Landau levels of composite fermions that is similar to
that of electrons. Observations of spin wave excitations enable determinations
of energies required to reverse spin. The spin reversal energies obtained from
the spectra illustrate the significant residual interactions of composite
fermions. At $\nu = 1/3$ energies of spin reversal modes are larger but
relatively close to spin conserving excitations that are linked to activated
transport. Predictions of composite fermion theory are in good quantitative
agreement with experimental results.
