Prior to the arrival of Europeans, the common nightcrawler, an annelid worm, was absent from much of the North American continent. Apparently, it had been wiped out by the glaciers of the last Ice Age. Use the Internet or the Strayer Library to research how the introduction of earthworms to North America occurred in the so-called Columbian Exchange. Discuss your findings. Based on what you researched, give your opinion about how it affected the environment.