(c) : Sea anemone is completely non-parasitic form. It shows the example of mutualism. Sea anemone attaches itself to shell used by a hermit crab. The anemone obtains nourishment from the scraps of food left by the crab, and is transported from place to place when the crab moves. The crab is protected by the stinging cells in the tentacles of sea anemone. Mosquito and leech are parasites of animals and feed on their blood. Tapeworm is a human gut parasite.