Fact 1: The Himalayas were formed by rock folding.

Fact 2: Folds are examples of ductile rock deformation.

Given the two facts above, answer the question "The Himalayas were formed by what?" with the following options: 
- fissures of hot, acidic water
 - Movement of an air mass
 - movements in the earth's crust
 - movement of tectonic plates
 - remains of prehistoric life
 - tectonic plates coliding
 - air mass over Earth's surface
 - ductile rock deformation


 

        ductile rock deformation 