Fact 1: Carbon may be stored in sedimentary rock for millions of years.

Fact 2: Sedimentary Rocks One of the commonest sedimentary rocks is sandstone.

Given the two facts above, answer the question "What element may be stored in sandstone for millions of years?" with the following options: 
- copper
 - calcium
 - carbon
 - chemicals
 - heat
 - iron
 - rock
 - fossils


 

   carbon      