Define category and hierarchy.

Explanation

**Step-by-Step Text Solution:**

1. **Definition of Category:**
- A category refers to a grouping system used in biological classification. It is a way to organize and classify organisms based on shared characteristics or traits. For example, in taxonomy, categories can include groups such as species, genus, family, order, class, phylum, and kingdom.

2. **Definition of Hierarchy:**
- Hierarchy refers to the arrangement of these categories in a specific order. In biological classification, this means organizing the categories from the most general to the most specific or vice versa. For instance, in the taxonomic hierarchy, the kingdom is the broadest category, followed by phylum, class, order, family, genus, and species, which is the most specific.

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