  [ABRIDGED] We have determined carbon abundances for 51 dwarf stars and
manganese abundances for 95 dwarf stars in two distinct and well defined
stellar populations - the Galactic thin and thick disks. As these two
populations have different chemical histories we have been able to, through a
differential abundance analysis using high-resolution spectra, constrain the
formation sites for carbon and manganese in the Galactic disk(s).
  The analysis of carbon is based on the forbidden [C I] line at 872.7 nm which
is an abundance indicator that is insensitive to errors in the stellar
atmosphere parameters. Combining these data with our previously published
oxygen abundances, based on the forbidden [O I] line at 630.0 nm, we can form
very robust [C/O] ratios that we then used to investigate the origin of carbon
and the chemical evolution of the Galactic thin and thick disks..... Our
interpretation of our abundance trends is that the sources that are responsible
for the carbon enrichment in the Galactic thin and thick disks have operated on
a time-scale very similar to those that are responsible for the Fe and Y
enrichment (i.e., SNIa and AGB stars, respectively).
  For manganese, when comparing our Mn abundances with O abundances for the
same stars we find that the abundance trends in the stars with kinematics
typical of the thick disk can be explained by metallicity dependent yields from
SN II. Furthermore, the [Mn/O] versus [O/H] trend in the halo is flat. We
conclude that the simplest interpretation of our data is that manganese most
likely is produced in SN II and that the Mn yields for such SNae must be
metallicity dependent.
