The study of the kind and diversity of organisms and the existing relationship among them is called A. Systematics B. Taxonomy C. Classification D. Nomenclature
Hint: Systematics in biology deals with the classification systems and nomenclature of organisms. It is essentially a branch of biology that studies the distinctive characteristics of species, and the way they're associated with other species.
Complete answer: Systematics can be further divided into two major divisions which are closely related to each other: taxonomy (known as the Linnaean System) and phylogeny. The correct sequence of groups that is universally accepted is ordered as Kingdom- Phylum- Class- Order- Family- Genus- Species. Carolus Linnaeus is famously considered as the father/founder of modern taxonomy and systematics. Systematics classifies organisms to construct internationally shared classification systems with each organism placed into more and more inclusive groupings. Popularly, classifications of living organisms arise consistently with the need to understand organisms better. A proper classification provides the idea for a comparatively uniformed, and internationally understood nomenclature, thereby simplifying the retrieval of data.
So, the correct answer is option A. Systematics.
Note: It is important to note that Systematics is often confused with taxonomy. Taxonomy essentially sets up arrangements of the sorts of plants and animals in hierarchies of superior and subordinate groups but it doesn’t involve the study of evolutionary histories of organisms, unlike systematics.