Answer:
Whether or not breakfast is provided
Explanation:
An independent variable is the variable in an experiment that is being changed. The dependent variable, by contrast, changes <em>because of</em> the independent variable.
In this case, children are either given breakfast or they are not. Since the scientists are choosing whether or not to give the children breakfast, that is the independent variable.
Thus, the independent variable is whether or not breakfast is provided.
Hope this helps!
