This document defines and provides examples of different kingdoms of life: Archaebacteria, Eubacteria, Protists, Fungi, Plants, and Animals. It explains that Archaebacteria and Eubacteria are the oldest and most simple forms of life, often single-celled, found in extreme environments. Protists are also microscopic single-celled organisms that are distinct from plants, animals, bacteria, and fungi. Fungi include mushrooms and molds, some important to ecosystems while others can cause disease. Plants are generally multi-cellular producers that generate their own food. Animals, the largest kingdom, are multi-cellular consumers that require eating other organisms for energy and nutrition.