Answer :
Final answer:
A keystone species is one that plays a crucial role in its community and affects the populations of many other species.
Explanation:
A keystone species is one that plays an especially important role in its community and has a significant impact on the populations of many other species. When the numbers of a keystone species change, it can cause major shifts in the ecosystem.
For example, sea stars are considered keystone species in coral reef communities. Sea stars prey on mussels and sea urchins, which have no other natural predators. If sea stars were removed from the coral reef community, the populations of mussels and sea urchins would explode and negatively impact many other species in the community, eventually destroying the coral reef ecosystem.
