  What the progenitors of Type Ia supernovae (SNe Ia) are, whether they are
near-Chandrasekhar mass or sub-Chandrasekhar mass white dwarfs, has been the
matter of debate for decades. Various observational hints are supporting both
models as the main progenitors. In this paper, we review the explosion physics
and the chemical abundance patterns of SNe Ia from these two classes of
progenitors. We will discuss how the observational data of SNe Ia, their
remnants, the Milky Way Galaxy, and galactic clusters can help us to determine
the essential features where numerical models of SNe Ia need to match.
