Which statement best captures the keystone species concept in coastal ecosystems?

• A. Sea otters in kelp forests regulate urchin populations, thereby preserving kelp habitat.
• B. Coral bleaching events are the sole driver of reef decline.
• C. A keystone species is a species whose removal leads to substantial changes in ecosystem structure.
• D. Seagrass beds have no significant effect on habitat complexity.

Answer: (C)