What common parasite is transmitted through the ingestion of infected fleas?

The correct answer is tapeworms because they specifically require fleas as an intermediate host for transmission. When an animal, such as a dog or cat, ingests an infected flea while grooming itself, it can also ingest the larval form of the tapeworm that the flea carries. Once inside the host's intestine, the tape-like tapeworm can mature and reproduce, leading to a tapeworm infection. This is a key characteristic of the life cycle of certain types of tapeworms, particularly Dipylidium caninum, which is the most common tapeworm associated with dogs and cats.

In contrast, heartworms are transmitted through the bite of infected mosquitoes, not through fleas. Roundworms and hookworms are also not directly associated with flea ingestion; roundworms are typically transmitted via contaminated soil or feces, while hookworms enter through the skin or through ingestion of infected soil. Thus, the unique relationship between fleas and tapeworms highlights why tapeworms are the correct answer in this context.