In the table below, which statement would best fill the missing box under isolated systems?
Open system
Matter freely moves
Energy freely moves
Isolated system
Matter does not freely move
A-Energy is variable
b-energy is not exchanged
C-Energy freely moves
D-Energy is destroyed

Rank the six combinations of electric charges on the basis of the electric force acting on q1. define forces pointing to the right as positive and forces pointing to the left as negative. rank positive forces as larger than negative forces. q1,q2,q3 = positive(+) q1 = + q2 = + q3 = - q1 = + q2= - q3= + q1= - q2= + q3= + q1= + q2= - q3= - q1,q2,q3 = negative