Problem: In modern taxonomy, Carl Woese and George Fox's genetics-based tree of life revealed significant differences in small subunit ribosomal RNA gene sequences among organisms, leading to the creation of three Domains: Archaea, Bacteria, and Eukarya. This discovery challenged traditional classification methods by highlighting the complexity of evolutionary relationships and the occurrence of which complicates the determination of organismal relatedness. Need Assignment Help? Select one: a. Endosymbiosis b. Genetic drift c. Convergent evolution d. Horizontal gene transfer