Answer:
preservation of original remains- when the original remain is still in the rock/dirt, typically shells and bones.
permineralization- when the pores of plant materials, bones, and shells are impregnated by mineral matter from the ground, lakes, or oceans
molds and casts- casts preserve a three-dimensional impression of remains buried in sediment, the mineralized impression of the organism left in the sediment is called a mold.
replacement- form when water dissolves away dead tissue and leaves minerals in its place.
compression- a fossil preserved in sedimentary rock that has undergone physical compression
petrifaction- when the organic plant or animal material is replaced with minerals and eventually hardens into rock