Predators that are keystone species can maintain species diversity in a community if they a. competitively exclude other predators. b. prey on the community's dominant species. c. reduce the number of disruptions in the community. d. prey only on the least abundant species in the community.

Verified step by step guidance

1. Step 1: Understand the concept of a keystone species. A keystone species is a species that has a disproportionately large effect on its environment relative to its abundance. These species play a critical role in maintaining the structure of an ecological community, affecting many other organisms in an ecosystem and helping to determine the types and numbers of various other species in the community.
2. Step 2: Analyze the options. Option a suggests that keystone predators maintain diversity by excluding other predators. This is not necessarily true, as the presence of multiple predators can also contribute to diversity. Option c suggests that keystone predators maintain diversity by reducing disruptions in the community. While stability can contribute to diversity, it's not the primary role of keystone predators.
3. Step 3: Consider option d, which suggests that keystone predators maintain diversity by preying only on the least abundant species. This is not typically how keystone predators operate. They often prey on a variety of species, not just the least abundant ones.
4. Step 4: Look at option b, which suggests that keystone predators maintain diversity by preying on the community's dominant species. This is typically how keystone predators operate. By preying on dominant species, they prevent those species from becoming too abundant, which can lead to a decrease in diversity.
5. Step 5: Based on the analysis of all the options, the correct answer is b. Keystone predators maintain species diversity in a community by preying on the community's dominant species.