Cysts of Protozoans Many protozoans convert into a cyst, a dehydrated, protective form of the organism when they encounter harsh environmental conditions. In a cyst form, the organism is able to survive a wide variety of environments and thus allows the organism to spread more easily. For a picture of a Giardia intestinalis cyst, click here . Fungi There are basically three types of fungi - mushrooms, molds and yeasts. On the other hand, the fungi known as yeasts consists of a single cell.
Fungi reproduce and spread by means of spores.
The life cycle of many helminths is complex and may involve more than one host. The definitive host is the host in which the sexually mature adult helminth lives. A list of parasites and their life cycles can be seen by clicking here . The flukes have a flat,leaf-shaped body with a ventral sucker and an oral sucker. Flukes are named according to where they live in the host.