  The moduli space $\bar{M}_A$ of weighted pointed stable curves of genus zero
is stratified according to the degeneration types of such curves. We show that
the homology groups of the moduli space $\bar{M}_A$ are generated by the strata
of $\bar{M}_A$ and give all additive relations between them. We also observe
that the Chow groups $A_i \bar{M}_A$ and the homology groups $H_{2i} \bar{M}_A$
are isomorphic. This generalizes Kontsevich-Manin's and Losev-Manin's theorems
to arbitrary weight data $A$.
