Biology

The correct answer is B.sea otters.

Sea otters are a classic example of a keystone species in coastal kelp forest ecosystems. They play a crucial role in maintaining the health of kelp forests by preying on sea urchins. Sea urchins are herbivores that graze on kelp, and if their population is not controlled, they can overgraze kelp forests, leading to their destruction. By keeping sea urchin populations in check, sea otters help maintain the balance of the ecosystem and ensure that kelp forests can thrive.

Why the other options are not correct:

A. Starfish: While some species of starfish can be important in marine ecosystems (such as the crown-of-thorns sta...