Movement can be without change in positions. As only a part of it can be made to move. If you move there is a motion and if there is a motion there is a movement so they're same thing. In motion whole of body moves, but in movements only the parts of body moves.
The Answer is C. The outer shell electrons are the electrons which are involved with chemical reactions and bonding. All elements in the same group have different number of total electrons but ALL have the same number of outer shell electrons. This is why they exhibit similar chemical properties.
