Read the following passage. Then complete parts a and b. The land area that became Yellowstone National Park originally had an important population of wolves. The wolves helped control the populations of multiple other species in the area. When wolves were overhunted and disappeared from the park, it affected the populations of many other species. When wolves were later successfully reintroduced, it helped restore the proper population levels for a wide variety of species, including elk, beavers, birds, and even certain species of trees and shrubs. (2 points)
a. Claim: Wolves must be blank because they have blank on the rest of their ecosystem.