The sea otters promote the growth of the kelp which is their favorite species, increasing their own population also.
Step-by-step explanation:
Sea otters focus on increasing the growth of the kelp and promote the growth of the kelp. The reason of the growth of the kelp is that this species is the most favorite species of the sea urchin grazers.
By the consumption of the kelp by the sea otters, the sea otters tend to protect the habitat of a lot of other populations which include the fish, birds and other marine animals.