Question

The allele for a widow’s peak has complete dominance over the allele for a straight hairline (w). What is the probability of a man with a straight hairline (ww) and a woman with a widow’s peak (WW) having an offspring without a widow’s peak?

Answer 1

There won't be any probability for any of the offspring without widow's peak, or there is 0 probability or there will be no offspring without widow's peak, this goes by the following mentioned cross
WW × ww
Gametes (haploid)
male W, W
Female w, w
F1 offspring all Ww
W (with widow's peak) completely dominant.