Parasitism
In parasitism, an individual organism, the parasite, consumes nutrients from another organism, its host, resulting in a decrease in fitness to the host. In extreme cases, parasites can cause disease in the host organism; in these situations, we refer to them as pathogens. We divide parasites into two categories:
endoparasites, which live inside the body of their hosts, and
ectoparasites, which live and feed on the outside of the body of their host













