Answer:
Independent variable: Different products of toothpaste
Dependent variable: Amount of plaque left in her teeth
Control group: Water
Constant: Same amount of time for product to have an effect
Step-by-step explanation:
Independent variable is the variable that is subject to manipulation or change by the experimenter in order to effect a measurable response. The independent variable in this experiment is the DIFFERENT PRODUCTS OF TOOTHPASTE USED.
The dependent variable is the variable that is measured during the experiment. In this experiment, the dependent variable is the AMOUNT OF PLAQUE LEFT IN ALEX'S TEETH.
The control group in an experiment is the group that does not receive the treatment/independent variable. In this case, the usage of WATER is the control.
The constant is the variable kept the same for all the groups in the experiment. In the case, the Same amount of time for each product to have an effect on her teeth is the CONSTANT.