In the last step of extracting energy from sugar, an enzyme called cytochrome c oxidase attaches electrons to oxygen and hydrogen ions, forming water. the electrons are temporarily bound to an iron atom in the enzyme before they are attached to oxygen. cyanide is a poison that acts by permanently binding to the enzyme near this iron atom, preventing oxygen from getting near enough to accept the electrons. how would you describe the action of cyanide?

Cyanide is an inhibitor.

Explanation:

The cytochrome C oxidase has an active site which is the iron atom. When the cyanide binds to the iron it's inhibiting the enzyme activity, because it's physically avoiding the oxygen (substrate) from binding to the active site. This can lower the enzyme activity or stop it completely.

parasites can detrimentally affect their host, but also must not allow their host to die before they can complete their life cycle. some parasites have complex life cycles with many different hosts, and have had to find ways of persisting in many different environments during the change from one host to another. ectoparasites live outside the body of the host, and can more easily  disperse, but are  more exposed to predators, parasites, parasitoids. endoparasites live inside the body of the host, and are therefore protected from the outside environment. but they can be  attacked by the host's immune system. they have therefore developed  mechanisms for dispersal such as  complex life cycles.