Answer:
The answer is explained below.
Step-by-step explanation:
Independent variable is the one that is changed and controlled: the nail polish Sarah uses.
Dependent variable is the one that is studied, the result of the dependent variable: how long the nail polish lasts.
Hypothesis is the statement that has to be proved or declined during the experiment: different nail polish lasts a different period of time without chipping.
The control group is the not exposed to changes and the independent variable is part of this group: when Sarah paints her nails (4 Sundays in a row) and the type of bottom coat and top coat as well as the weekly routine.
The experimental group contains the independent variable and it is changed for the group: the type of nail polish.
The constants are Sally since she performs the experiment; the period of research, the routine and the coats.