Final answer:
Mutualism is not an example of a parasite/host relationship because in mutualism, both species involved benefit, which is contrary to the nature of parasitism where the host is harmed.
Step-by-step explanation:
The option that is not an example of a parasite/host relationship is b) Mutualism. Mutualism is a symbiotic relationship in which both species benefit. This differs from a parasitic relationship where only one organism, the parasite, benefits at the expense of the other, known as the host.
An example of mutualism would be bees pollinating flowers while collecting nectar for food. On the other hand, parasitism is exemplified by a tapeworm in a mammal's intestines, where the tapeworm absorbs nutrients at the host's detriment. Commensalism involves one species benefiting while the other is unaffected, such as barnacles attaching to a whale, but does not constitute a parasite/host dynamic like parasitism. Therefore, mutualism does not represent a parasitic relationship as it involves mutual benefits rather than harm to one party.