Fact 1: Friction causes the speed of an object to decrease.

Fact 2: Friction is dependant on the texture of both surfaces.

Given the two facts above, answer the question "What can cause the speed of an object to decrease?" with the following options: 
- more propulsion
 - a tree falling
 - degrees Celsius
 - degrees celcius
 - texture of the surfaces
 - inertia
 - Electrical energy
 - sunlight


 

     texture of the surfaces    