(N/A) $\rightarrow$ Taxa: Each category referred to as a unit of classification represents a rank and is commonly termed as a taxon (plural: taxa).
$\rightarrow$ Dogs,cats,mammals,wheat,rice,plants,and animals are convenient categories we use to study organisms. The scientific term for these categories is taxa.
$\rightarrow$ Taxa can indicate categories at very different levels. For example,'plants' form a taxon,'wheat' is a taxon,and 'mammals' are also a taxon. Since a dog is a mammal and mammals are animals,these represent taxa at different levels.
$\rightarrow$ Taxonomy: Based on characteristics,all living organisms can be classified into different taxa. This process of classification is called taxonomy.
$\rightarrow$ External and internal structure,along with the structure of the cell,development process,and ecological information of organisms,are essential and form the basis of modern taxonomic studies. Characterization,identification,classification,and nomenclature are the processes basic to taxonomy.
$\rightarrow$ Systematics: Human beings have always been interested in knowing more about different kinds of organisms and their diversities,as well as the relationships among them. This branch of study is referred to as systematics.
$\rightarrow$ The word systematics is derived from the Latin word 'systema',which means the systematic arrangement of organisms. Linnaeus used 'Systema Naturae' as the title of his publication. The scope of systematics was later enlarged to include identification,nomenclature,and classification.