According to the theory of island biogeography, which of the following is not an island ecosystem? a. a mountain with thriving vegetation surrounded by an arid desert b. the open ocean c. grasslands that surround a lake d. a cave within the forests of the appalachian mountains in the eastern united states

A

Explanation:Its a mountain not a flat land or island

The correct answer is Option B- the open ocean.

Explanation:

The open ocean ecosystem are the ecosystem that is the area that includes above the seafloor and within the coastal margins. It ranges from the tropical to the polar regions.

The island ecosystem is the interaction of the island organism and ecosystem. According to the theory of island theory presented by MacArthur  and Wilson all three ecosystem mention in question are type of island ecosystem except the open ocean.

Thus, the correct answer is option B. the open ocean.