  The "kinematical" resolution of the $U_A(1)$ problem is proposed. The
cancellation of photonic and gluonic anomalies suggested by the t'Hooft
consistency principle naturally explains the zero singlet contributions to the
first moments of proton and photon spin structure functions. The new sum rule
for the photon spin structure function is derived. The strong strong
$Q^2$-dependence of the Gerasimov-Drell-Hearn sum rule is related to the $G_2$
structure function and to the gluonic anomaly.
