(i) Taxon is a group of organisms representing any level to category. For example, Sparrow, flatworm, lion, crocodile, etc.
(ii) Taxonomic hierarchy is the system of arranging taxonomic categories in a descending order with species at the base.
(iii) The number of individuals increases as we go up in a taxonomic hierarchy.
(iv) The number of shared or correlated characters decreases as we go up in a taxonomical hierarchy.