What two factors could the students change to investigate how to increase and decrease the magnetic force between the paperclip and the magnet?
A. Students could use a heavier retort stand and thicker string.
B. Students could change the color of the rock and the paperclip they are using.
C. Students could change the position of the clamp to move the magnet father away
from the paperclip.
D. Students could move the magnet further away from the paperclip and use a more
powerful magnet instead of a bar magnet.