The natural selection is the process that organisms in the same environment pass to adapt and survive, being the individuals in a population naturally variable, with some having better adaptive traits to survive in the environment than others. The population of mice that arrived on the island with abundant resources will also go through natural selection, being the correct alternative is the one that says: " yes, because natural selection always acts on populations", since it is a natural process that occurs with all the living organisms, regardless of the circumstances.