What type(s) of charges will be free to move around independently in a conductor under typical classroom conditions

An experiment is designed to test the relationship between the initial height of a basketball before it is dropped to the height of its rebound bounce. the height of the rebound bounce is measured using a scale positioned behind the ball. in the above experiment, which condition would not be controlled? a). the starting height of the ballb). the surface the ball bounces on c). the type of ball d). the method to measure the rebound height of the ball

Which object is most likely represented by a dot?

In a voltaic cell, electrons flow from the (positive/negative) to the (positive/negative) terminal.