Answer:
The independent variable is the amount of glucose being supplied and the dependent variable is the amount of alcohol being produced.
An independent variable can be described as the variable which is being changes in a scientific experiment so that its effects can be studies.
The dependent variable can be described as the variable which is under study and which gets affected by the changes in the independent variable.
The control that can be designed for this experiment can be another experiment in which the amount of glucose is kept constant in each of the yeasts.