Two plants with white flowers, each from true-breeding strains, were crossed. All the F₁ plants had red flowers. When these F₁ plants were intercrossed, they produced an F₂ consisting of 177 plants with red flowers and 142 with white flowers. 

(a) Propose an explanation for the inheritance of flower color in this plant species.
(b) Propose a biochemical pathway for flower pigmentation and indicate which genes control which steps in this pathway.