Fact 1: Vein deposits of gold and silver are formed by igneous intrusion.

Fact 2: Intrusive igneous rocks account for sections of higher elevation.

Given the two facts above, answer the question "vein deposits of gold and silver are formed where?" with the following options: 
- loose soil
 - aqueous solution
 - graptolites
 - tectonic plates coliding
 - higher elevations
 - mountain sources
 - flow of electrons
 - In sediment


 

     higher elevations    