Could someone help answer this biology question?

Fossils can only be formed when? if mud, silt or tar is in the area to preserve the fossil ierosion does not occur and allows the fossil to form oxygen and microorganisms cannot decay the bones the area is dry and does not contain mud or silt

Why is it important that fibrin is insoluble in water?

This is one of the five kingdoms in the older biological succession. organisms in this kingdom are prokaryotic