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.

Which statements best describe the differences or similarities between a comparative investigation and an experimental investigation? check all that apply. experimental investigations are best for showing cause-and-effect relationships, while comparative investigations do not necessarily show this type of relationship. comparative investigations are often impractical and unrealistic, while experimental investigations are the most practical and realistic kinds of investigations. comparative investigations allow for the use of a wide range of variables but do not have a control group, while experimental investigations involve variables that can be controlled. both experimental investigations and comparative investigations are designed to answer scientific questions. both experimental investigations and comparative investigations focus on making observations rather than collecting new data.