  We propose two new means of identifying the main class of progenitors of Type
Ia supernovae--single or double degenerate: (i) If the range of supernova
properties is significantly determined by the range of viewing angles of
non-spherically symmetric explosions, then the nature of the correlation
between polarization and another property (for example, the velocity gradient)
can be used to determine the geometry of the asymmetry and hence the nature of
the progenitor, and (ii) in the double- but not in the single-degenerate case,
the range in the observed properties (e.g., velocity gradients) is likely to
increase with the amount of carbon seen in the ejecta.
