  Presupernova evolution and explosive nucleosynthesis in massive stars for
main-sequence masses from 13 $M_\odot$ to 70 $M_\odot$ are calculated. We
examine the dependence of the supernova yields on the stellar mass,
$^{12}C(\alpha, \gamma) ^{16}O}$ rate, and explosion energy. The supernova
yields integrated over the initial mass function are compared with the solar
abundances.
