Biology

The independent variable in this experiment is:

Mass of the ball.

The independent variable is the factor that is deliberately changed or manipulated in an experiment to see how it affects the dependent variable. In this case, Mr. S. is testing how changes in the mass of the ball affect the distance it rolls off the ramp, so the mass is the independent variable.

Here's why the other options are not the independent variable:

A.Distance traveled by the ball: This is the dependent variable, which is what you're measuring in the experiment. It depends on the changes made to the independent variable (the mass of the ball).