The number of species on an island has remained stable over the past 200 years.This suggests that
A) extinction is not occurring.
B) immigration is not occurring.
C) immigration is constantly adding species to the island.
D) emigration is constantly removing species from the island.
E) the processes of extinction and immigration are balanced.

Question

Quizplus · Accepted Answer

The fact that the number of species on the island has remained stable suggests that the rate of extinction is counterbalanced by the rate of immigration. Therefore, the processes of extinction and immigration are balanced, making option E the correct answer. Option A is incorrect because it implies that no species have gone extinct, which is not necessarily true. Option B is also incorrect because it implies that no new species have immigrated to the island, which is also not necessarily true. Option C and D are incorrect because they suggest that only one process (immigration or emigration) is affecting the number of species on the island, when in fact both extinction and immigration are likely playing a role.

The Number of Species on an Island Has Remained Stable