The tapeworm Echinococcus granulosis has its life cycle in how many different host organisms?

The tapeworm Echinococcus granulosus primarily has a life cycle involving two different host organisms:

1. Definitive Hosts: These are usually canines, such as dogs, which carry the mature tapeworm in their intestines. The tapeworm produces eggs that are excreted in the feces of the definitive host.

2. Intermediate Hosts: These include livestock and humans. When these hosts ingest the eggs, the larvae can develop into cysts in their organs, causing health issues. Common intermediate hosts are sheep, goats, and various other mammals.

Overall, Echinococcus granulosus requires two types of hosts to complete its lifecycle: one for maturation (definitive host) and another for larval development (intermediate host).