You are presented with the question "what causes the speed of an object to decrease" and the following answer choices: 
- kilometers
 - kinetic energy
 - Electrical energy
 - increase h2o
 - principals of aerodynamics
 - basic building blocks of life
 - opposing motion force
 - increase oxygen

Now knowing that friction causes the speed of an object to decrease and friction is a Force that opposes motion, choose the best answer.


 

       opposing motion force  