Protozoans- A protozoan is a one celled organism. These invertabrates are not male nor female. They are produced by fission which is a simple cell division. This process can take less than an hour in favorable conditions. When water is not available they create a hard covering over their newly formed individuals. They can lie dormant in the absence of water and survive until water returns. Protozoans feed off of living things, required that they spend different parts of their lives inside different animals. We humans do not directly encounter protozoans in the every day course of life.
