Descending arrangement of categories is called

The correct option is hierarchy.

Explanation:
In biological classification, organisms are categorized into a multi-level structure where each level represents a specific rank. The arrangement of these taxonomic categories in a descending (from highest to lowest) or ascending (from lowest to highest) order is known as a hierarchy (specifically, the taxonomic hierarchy).

Let us break down the terms to understand their meanings:
1. Hierarchy: This refers to a system of ranking one above another. The standard descending biological hierarchy is:
Kingdom ⇒ Phylum (or Division) ⇒ Class ⇒ Order ⇒ Family ⇒ Genus ⇒ Species.
2. Taxonomy: This is the broad scientific study of naming, defining, and classifying groups of biological organisms.
3. Classification: This is the method of arranging organisms into groups based on their similarities and differences.
4. Characterization: This is the process of understanding and listing the distinct traits or features of an organism.

Therefore, the descending arrangement of categories is specifically called a hierarchy.