BUT, people who eat the mollusks are - some die. The covering of many is composed of cellulose plants. Protozoan means first animal. There are 65,00 species - many of which are parasites. Protozoans are grouped according to their means of locomotion.
None are photosythetic.
Flagellated There are free living and parasitic forms. Cysts contaminate the water supply. Amoeboid All use a pseudopod for locomotion or for feeding. Sporozoan All are parasites. They have a spore-like stage in the life cycle.