Answer:
so that a fossil can be formed, it is necessary that the body of the organism is just under the appropriate environmental and physical conditions. When this happens it is possible that the whole body or some of its parts are preserved and fossilized. It is important that there are sediments for the body to be covered. Then and through the passage of many years there is an exchange between organic matter and minerals. When the remains of the organism are mineralized, it can be considered as a fossil. This form of fossilization is called mineralization. In this process, the water is filtered after layers and layers of soil and the water carries minerals to the bones, gradually turning them into rock.
It can also happen that the organism is practically preserved as in life. It is necessary for the animal to be trapped in a waterproof and resistant to decomposition material, such as amber or ice. It is called mummification.