Question

An individual hydra is swept by an ocean current to an area of the ocean where no other hydras reside. The hydra asexually reproduces, as does its offspring, until there is a population of genetically identical hydra. Is it possible for this population to undergo natural selection?

No, natural selection does not occur in organisms that reproduce asexually.
Yes, the population will undergo changes in order to become better adapted to the new environment.
Yes, all populations are capable of undergoing natural selection.
No, there is no genetic variation upon which natural selection can operate.