You are presented with the question "Chemical weathering causes iron in rock to combine with what?" and the following answer choices: 
- uranium
 - oxygen
 - cartilage
 - nothing
 - an object
 - vacuum
 - energy
 - heat

Now knowing that chemical weathering causes iron in rock to oxidize and oxides Oxides Oxides are elements combined with oxygen, choose the best answer.


 

  oxygen       