  By scaling the parameters of meson-meson unitarized Chiral Perturbation
Theory amplitudes according to the QCD large N_c rules, one can study the
spectroscopic nature of light meson resonances. The scalars sigma, kappa
f_0(980) and, possibly, the a_0(980) do not seem to behave as q-qbar states, in
contrast to the vectors rho(770) and K*(892). The behavior shown by the scalars
is naturally explained in terms of diagrams with intermediate $\bar q\bar q
qq$-like states. Here we review our recent study and show how the results do
not depend on the different fits to data.
