Answer:
Organic matter produced when an organism is alive remains unchanged in unaltered fossil while the opposite happens in cases of altered fossil
Explanation:
When the organic material produced by an organism during the time period when it was alive remains unchanged in the given course of time then it is termed as unaltered or original preservation. for example - bones, teeth etc, remain intact.
While in case if the organic material produced by an organism during the time period when it was alive changes in due course of time by the external forces is called as altered fossil
