Fact 1: Folding an object causes that object to change shape.

Fact 2: Tri-folds and half folds are acceptable if machine folded.

Given the two facts above, answer the question "What can cause objects to change shape?" with the following options: 
- Pulleys
 - a prism
 - Machines
 - Heat energy
 - Animals
 - mechanical
 - Lifts
 - Temperature


 

   Machines      