Fact 1: Avalley is formed by a river flowing.

Fact 2: And from the spring there flows a river.

Given the two facts above, answer the question "the output of a spring can eventually form a what?" with the following options: 
- voltage
 - rain
 - power
 - dormant
 - valley
 - mountain
 - skyscraper
 - goldmine


 

     valley    