Protozoa (from the Greek words πρωτό, proto, meaning first, and ζωα, zoa, meaning animals; singular protozoon or also protozoan) are a diverse group of single-cell eukaryotic organisms, many of which are motile. Throughout history, protozoa have been defined as single-cell protists with animal-like behavior, e.g., movement. Protozoa were regarded as the partner group of protists to protophyta, which have plant-like behaviour, e.g., photosynthesis. However, they are already for long time regarded as an independent phyllum. Despite this, the former concept is stil educated on high and basic schools, therefore, is respected (although invalid) also in this virtual museum to enable easy searching and orientation of visitor.