Unicellular organisms are also known as microorganisms or single-celled organisms. These tiny life forms consist of only one cell, which carries out all the functions necessary for life. Examples of unicellular organisms include bacteria, protozoa, algae, and some fungi.
The classification of these organisms as microorganisms highlights their size and the fact that they are often too small to be seen with the naked eye, requiring a microscope for observation. Despite their simplicity, unicellular organisms are incredibly diverse and play a crucial role in various ecosystems, including human health, where they can be both beneficial and harmful.