Phenotypes are the physical characteristics that result from the genotype, which is the genetic makeup of the organism. In this case, either straight hairline or Widow's peak will be the phenotype, as they are the physical characteristics being discussed.
The questions states that a Widow's peak is dominant over straight hairline. So we are going to assume that the Widow's peak allele is W (dominant), and the straight hairline allele is w (recessive).
A dominant allele will mask the presence of a recessive allele unless both of the alleles are both recessive (both ww).
So for the WW genotype, we are going to see the dominant phenotype: Widow's peak.
For the Ww genotype, we are also going to see the dominant phenotype since the dominant allele is going to mask the presence of the recessive allele, so we are going to see: Widow's peak.
Lastly, for the ww genotype, we are going to now see the recessive phenotype, since both alleles are recessive: straight hairline. Note that their are two of these type of offspring as stated in the question.
