Answer:
Independent variable: Different tyre treads
Dependent variable: Breaking distance
Constant: Same car
Explanation:
In an experiment, an independent variable is that variable which the experimenter controls or manipulates to effect an outcome. In this experiment, the tyre treads are changed to see if it would affect the breaking distance, hence, the DIFFERENT TYRE TREADS is the independent variable.
On the other hand, a dependent variable is the variable that responds to the manipulation of the independent variable. In other words, it is the outcome of the experiment. In this experiment, the BREAKING DISTANCE is the responding or dependent variable.
Constant or controlled variable is that variable that is kept constant or unchanged throughout the course of the experiment. The constant, if changed, will influence the result of the experiment. The constant in this experiment is the CAR since the same car (unchanged) was used for the experiment.