Chemical weathering causes iron in rock to oxidize, and iron oxide gives a rusty red color to sedimentary rocks. Given these facts, what gives a rusty red color to sedimentary rocks among the following options:
- food coloring
 - The area was once underwater
 - chemical weathering
 - remains of prehistoric life
 - deoxyribonucleic acid
 - sea urchins
 - dirt
 - earthquakes


 

   chemical weathering      