Final answer:
Flame cells are primitive excretory organs found in flatworms. They have cilia that propel waste matter out of the body through excretory pores.
Step-by-step explanation:
Flame cells are primitive excretory organs found in flatworms. Flatworms, including parasitic tapeworms and free-living planaria, have an excretory system consisting of tubules connected to a duct system. The cells in these tubules, known as flame cells or protonephridia, have cilia that propel waste matter down the tubules and out of the body through excretory pores.