This document discusses different types of microorganisms including viruses, bacteria, protozoa, algae, and fungi. It describes their key characteristics such as appearance, size, shape, nutrition, reproduction methods, and habitats. Viruses are the smallest and can only reproduce inside host cells. Bacteria are larger and can move using flagella or pili. Protozoa include amoebas and paramecium which use pseudopodia to move and feed. Algae such as euglena are single-celled while spirigyra are multi-cellular and reproduce through conjugation. Fungi lack chlorophyll and feed on dead matter.