Answer:
In biology, osmosis is defined as the net movement of water molecules through a semipermeable membrane (e.g. cell membrane) from an area of higher to an area of lower water potential. Other definitions of osmosis are as follows:
The process of a solvent diffusing through a semipermeable membrane from an area of low solute concentration to an area of high solute concentration
The tendency of water to flow from a hypotonic solution (low concentration of dissolved substances) to hypertonic solution (higher concentration of dissolved substances) across a semipermeable membrane
In chemistry, osmosis is defined similarly. It is the passage of a pure solvent from a solution of lesser to one of greater concentration of solutes when the two solutions are separated by a membrane that selectively prevents the passage of solute molecules while allows the solvent molecules to pass through.
For more information see https://www.biologyonline.com/dictionary/osmosis
Many of the organisms that had existed on the earth left no fossils because most of them can not meet the conditions that must be fulfilled before fossils can form. For fossils formation to occur, the organism soft tissue must decay leaving behind the hard part [majorly bone] in the sediment. Overtime, layers of sediment have to build up and pressed down on the buried remains. As time goes on, water and mineral seeped into the remains and form crystals.