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

Fact 2: Limestone is a fairly common rock type.

Given the two facts above, answer the question "chemical weathering causes iron to oxidize in what?" with the following options: 
- calcite
 - limestone
 - In sediment
 - the skin
 - graptolites
 - loose soil
 - body water
 - soils


 

  limestone       