Marcos's study suggested that elementary students who watch tv more than three hours a day are more likely to be overweight than students who watch less tv. in this study, students' weight is:

From the question given it is clear that students’ weight, in this research, functions as the dependent variable.

The research that Marco is conducting is an experimental study, since he wishes to know whether the length of time the children spent watching television would influence their body weight. In this case, the independent variable is the TV-watching time while the dependent variable is the body weight.

answer; /// the correct answer is (a) burned the city;