You are presented with the question "What covers remains to create fossils?" and the following answer choices: 
- Sand and mud
 - Oxygen and water
 - Calcium carbonate
 - Volcanic ash
 - shells
 - some invertebrates
 - Water and oil
 - detritus

Now knowing that fossils are formed when layers of sediment cover the remains of organisms over time and sand and mud are examples of sediments, choose the best answer.


 

 Sand and mud        