You are presented with the question "What causes iron in asteroids to oxidize?" and the following answer choices: 
- aliens
 - chemical weathering
 - flow of electrons
 - hydrogen and oxygen
 - water
 - Chemical energy
 - fossil fuels
 - ice

Now knowing that chemical weathering causes iron in rock to oxidize and asteroids are typically made of rock or iron, choose the best answer.


 

  chemical weathering       