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?
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
In order to determine whether either one of Mary's parents is homozygous dominant or recessive, we need to consider the inheritance pattern of the Widow's peak and smooth hairline traits.
The Widow's peak trait is controlled by a single gene with two possible alleles: W (dominant) and w (recessive). Similarly, the smooth hairline trait is controlled by the allele w.
From the given information, we know that Mary has a widow's peak (either WW or Ww) and her sister has a smooth hairline (ww). This tells us that Mary must have inherited the allele for the widow's peak from one of her parents, and since her sister has a trait that is expressed only in the homozygous recessive form (ww), it is likely that her other parent carries the recessive allele for smooth hairline.
Based on these observations, we can conclude that at least one of Mary's parents must be heterozygous (Ww) for the widow's peak trait. Mary inherited one of the W alleles from this parent, while her sister inherited the recessive w allele.
To determine if either parent is homozygous dominant or recessive, we would need additional genetic data, such as the traits of Mary's grandparents or any siblings she may have. Without this information, we cannot definitively determine the homozygosity of her parents.