What was the significance of Freedom Summer? A
It was the first time an African American labor union was established.

B
It was an attempt by volunteers to register African American voters in Mississippi.

C
It signaled an end to school segregation in Alabama, Virginia, and South Carolina.

D
It resulted in the arrest of Martin Luther King, Jr. in Selma, Alabama.

Martha participates in a research study in order to receive extra credit for her psychology class. when she arrives in the research office she is given a can of what looks and tastes like beer, but which actually contains no alcohol. in the adjoining room martha's classmate karen is also participating in the study. karen receives a can of alcoholic beer. if the experiment was designed to test the effects of alcohol on concentration, then who is exposed to the independent variable?