The organisms fleas and lice are cited as examples of which lifecycle type?

• A. Direct lifecycles
• B. Indirect lifecycles
• C. Complex lifecycles
• D. Asexual lifecycles

Answer: (A)

Direct lifecycles are those in which the parasite can complete its development without needing an intermediate host. Fleas and lice fit this because, while some stages occur off the host (eggs/nits on the host or in the surrounding environment), the life cycle can be completed within the same host species without transferring through another animal. The parasite relies on the host itself for maturation to the adult stage and transmission to new hosts occurs directly, not via a different species. In contrast, indirect or complex lifecycles require one or more intermediate hosts and multiple species to finish development, and asexual lifecycles describe a reproduction mode rather than how the life cycle moves between hosts.