The right answer is C.
Classically positive interactions or facilitators between species are divided into two broad categories:
- those where the two partners involved benefit from each other: the mutualisms (symbolized by + / +)
- those where one of the two partners makes a profit or an advantage while the other gets nothing from it without being affected negatively: it is the commensalism symbolized by + / 0.
It may be that bacterial commensalism has an interest in its host (the animal) in the sense that it protects against parasites, or on the contrary, it favors their appearance.
To bring oxygen in the body because it is a respiratory organ fish
10-15% of energy is transferred between a producer and primary consumer.
