Final answer:
The three boxes at the base of a hierarchical diagram represent domains, which are the broadest category in the biological taxonomic system. There are three domains: Bacteria, Archaea, and Eukarya, under which there are multiple kingdoms and more specific categories down to the species level.
Step-by-step explanation:
The question pertains to the classification hierarchy of a cow, specifically Bos primigenius, and asks to identify the three boxes at the base of a hierarchical diagram. Based on the given context, the correct answer here is B. domains. This is because the hierarchy starts with the broadest category known as a domain, and narrows down to the most specific, which is the species.
Within the biological taxonomic system, there are three domains: Bacteria, Archaea, and Eukarya. Under each domain are multiple kingdoms, which are more specific than domains but less specific than the subsequent categories of phylum, class, order, family, genus, and finally, species.
In this system, humans, for example, belong to the domain Eukarya, kingdom Animalia, phylum Chordata, class Mammalia, order Primates, family Hominidae, genus Homo, and species sapiens. Similarly, a cow would belong to the domain Eukarya, which houses multicellular organisms with complex cell structures, indicating the vast scope of biological diversity represented within each domain. Each step down this hierarchy represents a more specific and narrowly defined group of organisms with shared characteristics.