A note on Mumford-Roitman argument on Chow schemes

In this note we are going to understand two questions. One is the fiber of the natural map from a projective algebraic group $G$ to $G/\Gamma$, where $\Gamma$ denotes the $\Gamma$-equivalence on $G$. The other one is to define a natural map from Hilbert scheme of the generic fiber of a fibration $X\to S$ to the Chow group of relative zero cycles on $X\to S$ and to understand the fibers of this map.