Answer the following question given this paragraph: 

Molds and casts are another way organisms can be fossilized. A mold is an imprint of an organism left in rock. The organism's remains break down completely. Rock that fills in the mold resembles the original remains. The fossil that forms in the mold is called a cast ( Figure below ). Molds and casts usually form in sedimentary rock. With compression ( Figure below ), an organism's remains are put under great pressure inside rock layers. This leaves behind a dark stain in the rock.


Q: Molds and casts usually form in which type of rock?

 Choices:

- igneous

- metamorphic

- crystalline

- sedimentary

A:
sedimentary
