Question
1) Mary has a widow's peak (either WW or Ww), but her sister has a smooth hairline (must be ww). Is either one of Mary's parents homozygous dominant or recessive? I think that that she has to have at least one of her two parents be homozygous something in order for this to work?
Answers
PsyDAG
Since sister is ww, must have received w from each parent. Both parents would be Ww or one Ww and the other ww.. Try a punnett square.
https://www.google.com/search?client=safari&rls=en&q=punnett+square&ie=UTF-8&oe=UTF-8
https://www.google.com/search?client=safari&rls=en&q=punnett+square&ie=UTF-8&oe=UTF-8