Final answer:
Organisms are classified into six kingdoms: Bacteria, Archaea, Protista, Plantae, Fungi, and Animalia. The classification starts with the broadest category, the domain, and becomes more specific with each subsequent category.
Step-by-step explanation:
In modern taxonomy, organisms are classified into six kingdoms: Kingdom Bacteria, Kingdom Archaea, Kingdom Protista, Kingdom Plantae, Kingdom Fungi, and Kingdom Animalia. The traditional five-kingdom system was expanded to include three domains: Bacteria, Archaea, and Eukarya. The classification system starts with the broadest category, the domain, and becomes more specific with each subsequent category, such as kingdom, phylum, class, order, family, genus, and species. The goal of taxonomy is to organize the millions of organisms on Earth based on their evolutionary relationships.