Which of the Following Organisms Is Lacking One of the Five

Multiple Choice

Which of the following organisms is lacking one of the five characteristics typically found in animals?

A) sponges, which have no true tissues but have two layers of cells that perform different functions
B) planaria, who have an incomplete digestive tract but do have muscles and excretory and reproductive systems
C) trypanosome, a single-celled organism that causes sleeping sickness in humans
D) leeches, segmented worms that are predatory on other animals
E) tapeworms, flatworms that infest the intestines of humans