2. A friend has a dog with a tapeworm problem. The dog is four years old and has been kept indoors its entire life. However, I shares the house with a cat that's let out each night. The dog has been treated several times with a drug. After each
treatment the proglottids stopped appearing in the feces. However, after about two weeks, they begin to reappear. Why can't
your friend get rid of the dog's infection?