A protista can be a producer, a consumer and a decomposer. They are unicellular or multicellular and it includes nucleus and organelles cells that can do all the life processes. As a consumer ie lives off other organisms it is an amoeba and includes malaria or skeeping sickness. As a producer it hss chlorophyll and can make their own food used in toothpaste and ice cream. As a decomposer it causes food spoilage and slime mold.