Scientists have been monitoring a population of Adelie penguins on Anvers island in Antarctica. The scientists recently noticed that there has been a large amount of emigration onto neighboring islands. However, the waters around these nearby islands do not supply as much food and are thus not optimal habitats for the penguins. Which of the following is the best explanation for the emigration behavior of the penguins? A. Killer whales (a common predator of Adelie penguins) have appeared in waters around Anvers Island. B. Killer whales (a common predator of Adelie penguins) have appeared in waters around the neighboring islands. C. A decline in the penguin population size has caused them to emigrate. None of these choices are plausible explanations. D. The penguins move to neighboring islands every few years.

In spite of the lack of food and unfavorable living conditions, the colony of Adelie penguins has emigrated onto neighboring islands to avoid the killer whales noticed around Anvers island in Antarctica. As a consequence, the penguins' survival instinct has caused them to eventually move to other islands, disregarding of their habitats.