Answer:
The independent variable is the height from which the ball is dropped.
for the second part what is changed is the Height from which the ball is dropped (B)
Step-by-step explanation:
An independent variable is a factor that is completely subject to the control of the scientist, that is the variable which the scientist can change at will. In this case, the independent variable is the height from which the ball is dropped because the student will drop the ball from different heights pre-determined by him, inorder to study and record the effect of how it affects the height to which the ball bounces, which then becomes the dependent variable.
so the height is changed.