In a modern system of classification, two organisms would be most closely related if they were classified in the same A. kingdom B. genus C. phylum D. species

In a modern system of classification, two organisms would be most closely related if they were classified in the same D. species. Species is the smallest and most specific unit of classification, and two organisms that belong to the same species are the most similar and closely related to each other. Kingdom, genus, and phylum are broader categories that encompass a larger group of organisms with varying degrees of similarity.