A commensalistic relationship is one sides but neutral for the other party. Barnacles live on whales but whales are not directly affected by them. I do not believe the barnacle population decrease would affect whales at all.
What are we supposed to do?
A is the answer for this question
Answer:
The structural adaptations of the flying squirrel has developed a good sense of balance, sail-like fur skin membrane that extends from the wrists to ankles, delicate wrist bones that control this membrane, allowing the squirrel to steer, and a fluffy tail that balances out and stabilizes the flight.