All of the following are true of the Zebra mussels found in the Great Lakes EXCEPT: a. Zebra mussels are having are having a negative impact on the native population of mussels in the region. b. They were unintentionally introduced to the Great Lakes by humans. c. Zebra mussels have caused a great deal of environmental damage to the area. d. People of the Great Lake region are benefitting from the economic advantages of having zebra mussels in the region.