You are presented with the question "what causes an object to lose energy?" and the following answer choices: 
- high temperature
 - electron transport
 - degrees celcius
 - surfaces rubbing together
 - heat is produced
 - degrees Celsius
 - depress neuronal excitability
 - a tree falling

Now knowing that friction causes an object to lose energy and friction occurs when surfaces rub together, choose the best answer.


 

    surfaces rubbing together     