Kelp forest and sea otter game

In the kelp forest, it eats sea urchins and other animals that graze on giant kelp. When urchins go unchecked, they create areas called “urchin barrens” where nothing else lives. With sea otters helping to keep the urchins under control, kelp forests can thrive and support a rich community of plants and animals.

This is giving me a headache i have asked others and they don’t know it either