  In combined 2- and 3-channel analyses of experimental data on the coupled
processes $\pi\pi\to\pi\pi,K\bar{K},\eta\eta$ in the channel with
$I^GJ^{PC}=0^+0^{++}$, various scenarios of these reactions(with different
numbers of resonances) are considered. In a model-independent approach,
confirmation of the $\sigma$-meson below 1 GeV and definite indications of the
QCD nature of other $f_0$ resonances are obtained. The conclusion on the linear
realization of chiral symmetry is drawn.
