25. A cross is made between two different true-breeding strains of daylilies, both of which have white flowers. All of the F1 generation plants have yellow flowers. When an F, offspring is crossed with either one of the parental strains, half of the offspring have yellow flowers and half of them have white flowers. Propose an explanation for this outcome. In your answer, you should describe the genotypes of the two parental strains and the F1 offspring, and also explain which alleles are loss-of- function and which are needed for yellow-flower color.