Which answer is not classified as an ectoparasite?

Ectoparasites are organisms that live on the outside of a host and feed off it, often leading to harm or distress for the host. Common examples include fleas, ticks, and lice, all of which attach to the skin or feathers of their hosts to feed on blood or other bodily fluids.

Tapeworms, on the other hand, belong to a different category of parasites known as endoparasites. They live inside the host's body, particularly in the intestinal tract, where they absorb nutrients from the host's digested food. This internal lifestyle distinctly separates tapeworms from ectoparasites, which are always found on the surface of the host.

In summary, while fleas, ticks, and lice are all examples of ectoparasites that interact closely with the host's skin or external structures, tapeworms are classified as endoparasites due to their internal habitat.