Tapeworm are particular species of worm that resides in the small intestine of mammals ( including humans ). The tapeworm latches on to the walls of the small intestine, and siphons ( steals ) nutrients from the mammals digestive tract. This can cause severe nutrient deficiency, weakness, and extreme weight-loss for the mammal. Organism 1 : ( can it be benefit or not ) Organism 2 : ( can it be harmed or neutral ) Symbiotic relationship: