  The polarized structure functions of $^3He$ and $^3H$ nuclei are calculated
in NLO approximation, considering and disregarding the light sea quark symmetry
breaking. We employ the polarized structure function of the nucleons within the
nucleus extracted from our two recent analysis on polarized DIS data and on
polarized DIS+SIDIS data. Since the data of the second analysis cover a bigger
range of Bjorken variable, both SU(2) and SU(3) symmetry breaking is considered
within the analysis. Then we calculate and compare the polarized structures of
nuclei extracted from both scenarios. Also the Bjorken and ELT sum rules are
calculated using the moments of structure functions. The results are compared
with experimental data and the differences are investigated.
