Fact 1: Tectonic plates being pushed together causes earthquakes.

Fact 2: Several tectonic plates make up the earth's crust that are in a constant state of process.

Given the two facts above, answer the question "Parts of the Earth's crust being pushed together causes what?" with the following options: 
- magnetic shifts
 - erosion
 - friction
 - earthquakes
 - solar flares
 - moonquakes
 - global warming
 - Sediment


 

    earthquakes     