You are presented with the question "What element may be stored in sandstone for millions of years?" and the following answer choices: 
- copper
 - calcium
 - carbon
 - chemicals
 - heat
 - iron
 - rock
 - fossils

Now knowing that carbon may be stored in sedimentary rock for millions of years and sedimentary Rocks One of the commonest sedimentary rocks is sandstone, choose the best answer.


 

   carbon      