<span>Fossils usually only form in sedimentary rock. Sediments have to accumulate over the organism in order to preserve it. This could be a rapid burial, such as a volcanic eruption or mudslide, it could be sap from a tree oozing over an insect, or simply a slow sediment accumulation on the bottom of a lake.</span>
An ecosystem refers to the animals, plants, and microorganisms that live in one place, ... of many North American species are moving north and to higher elevations