A researcher finds that blood alcohol levels cause progressive damage to the liver. All the mice in his study were fed the same amount and types of food. Different concentrations of alcohol were injected into each mouse. One group of mice does not receive any alcohol at all. The different concentration of alcohol injected into different mice represents the ______________________.
Independent variable, because it is not dependent on the other variables, because the researcher manipulates that variable and decides how much each mouse gets.
