  The Bethe-Salpeter equation for two massive scalar particles interacting by
scalar massless exchange has solutions of two types, which differ from each
other by their behavior in the non-relativistic limit: the normal solutions
which turn into the Coulomb ones and the "abnormal" solutions. The latter ones
have no non-relativistic counterparts and disappear in the non-relativistic
limit. We studied the composition of all these states. It turns out that the
normal states, even for large binding energy, are dominated by two massive
particles. Whereas, the contribution of the two-body sector into the abnormal
states, even for small binding energy, is of the order of 1% only; they are
dominated by an indefinite number of the massless particles. The elastic
electromagnetic form factors for both normal and abnormal states, as well as
the transition ones between them, are calculated.
