The termite gut protist, Mixotricha paradoxa, has at least two kinds of bacteria attached to its outer surface. One kind is a spirochete that propels its host through the termite gut. A second type of bacteria synthesizes ATP, some of which is used by the spirochetes. The locomotion provided by the spirochetes introduces the ATP-producing bacteria to new food sources. Which term(s) is (are) applicable to the relationship between the two kinds of bacteria?
1. mutualism
2. parasitism
3. symbiosis
4. metabolic cooperation

Mixotricha paradoxa forms symbiotic relationships (Symbiosis is a relationship between two or more organisms that live closely together) with the termite.

Part of the morphological characteristics of the Mixotricha paradoxa are the presence of "at least two kinds of bacteria attached to its outer surface." This morphological characteristics assist the termites in alot of ways. One of this kind of he spirochete propels its host through the termite gut. A second type of bacteria synthesizes ATP, some of which is used by the spirochetes. The locomotion provided by the spirochetes introduces the ATP-producing bacteria to new food sources. (mutualism)

Mixotricha paradoxa helps to digests cellulose for the termite. We can now conclude that Mixotricha forms a mutualistic relationships (mutualism) with bacteria living inside the termite. This is because the termite has spherical bacteria inside the cell which function as mitochondria, which Mixotricha lacks.

The Mixotricha are also organized into layers of tissue. Without their presence in the termite gut, the termites would die because Mixotricha keep the species intact, but they are harmful in an indirect way (parasitism).