Answer:
B.Wolves reintroduced --> elk decline --> willows increase --> beavers increase
Explanation:
Interrelatedness can be observed in the ecosystem of Yellowtone, in which species interaction is key to maintaining a balance in the ecosystem. Option B represents a correct example of interrelatedness.
Wolves prey on elk, thereby reducing the population of elk they browse on willows. The control of the population of elk would lead to the increase of willows as well as allow for their massive growth. These willows are very important to beavers. More willows would mean more beavers. Beavers gnaw on huge willows which they use in constructing dams to slow down water flow. Beavers do not really love rivers that flow fast, and so rely on willows to make dams.