Chemical Evolution of M31
  We review chemical evolution models developed for M31 as well as the
abundance determinations available for this galaxy. Then we present a recent
chemical evolution model for M31 including radial gas flows and galactic
fountains along the disk, as well as a model for the bulge. Our models are
predicting the evolution of the abundances of several chemical species such as
H, He, C, N, O, Ne, Mg, Si, S, Ca and Fe. From comparison between model
predictions and observations we can derive some constraints on the evolution of
the disk and the bulge of M31. We reach the conclusions that Andromeda must
have evolved faster than the Milky Way and inside-out, and that its bulge
formed much faster than the disk on a timescale $\leq$ 0.5 Gyr. Finally, we
present a study where we apply the model developed for the disk of M31 in order
to study the probability of finding galactic habitable zones in this galaxy.
