Question: The American Chestnut Tree, which once made up more than 25% of North American hardwoodforests, were killed off by a deadly fungal blight that does not affect the closely related AsianChestnut Tree. It is believed that the fungus was accidentally imported with Asian Chestnuttrees imported as ornamentals. Why do you suppose the fungus affects only the North American trees? What does this tell you about the importance of careful control of imported species? Do you think that such accidental importation of pathogens (of plants, animals, etc.) will become more frequent or more rare in the future? Why?