Students design an experiment to determine how much force is needed to move blocks of wood of different masses slowly across a lab table.
Which procedure should students include in their design?
A. conduct 5 trials, using a different scale to pull each block of wood
B. conduct 5 trials, pulling a different side of each block each time
C. conduct 5 trials, using a different table for each trial
D. conduct 5 trials, pulling each block of wood in the same way for each trial
