Answer:
Water is a control
Step-by-step explanation:
From the question, the independent variable is energy drink and the dependent variable is running 50 yard of ash.
An independent variable is a variable that can stand alone in an experiment.
Dependent variable is a variable that is beeping altered, tested and measured and it's dependent on the independent variable.
The running of 50 yard Yash depend on the energy drink which is independent.
Water is a control because it is not tested for dependent variable and it's minimize the effect of dependent variable. This is because the energy drink give energy to run 50 yard Yash and that is the dependent variable.