jobs, divorce between parents, money cutts,education,healthy environment
By the melting of the polar caps. This causes a rise in sea level thus flooding lands that people lived on. this in turn forces people to move.
Well you see the people with the money buy the candy for the movie!
The force that causes objects to move downward is gravity
The wind causes movement
Plate Activity causes it to move.
the muscles
Your prescription can get weaker. It often happens as people move out of middle age. There are other minor causes, as well.
The energy in your body gives you the fuel to move and gravity allows you to move at the speed you move but you move at your own will.
Energy
Muscles
contracting.
Randomism .