Fossils are formed when layers of sediment cover the remains of organisms over time.
Sand and mud are examples of sediments.
Fossils are formed with sand and mud cover the remains over time.
What covers remains to create fossils?

a) Sand and mud
b) Oxygen and water
c) Calcium carbonate
d) Volcanic ash
e) shells
f) some invertebrates
g) Water and oil
h) detritus