Fact 1: Chemical weathering causes iron in rock to oxidize.

Fact 2: Low rainfall means slow chemical weathering of rock.

Given the two facts above, answer the question "What can lead to oxidation of iron in rock?" with the following options: 
- heat energy
 - low rainfall
 - flow of electrons
 - permineralization
 - fossil fuels
 - harmful substances
 - boiling
 - evaporation


 

  low rainfall       