What is the process of changing the hard parts of an animal or plant with minerals

Calcification or replacement is the process of changing the hard parts of an animal or plant with minerals

Explanation:

It's  also called fossilization, and in particular, replacement and recrystallization. When we dig and get the bones of dinosaur, but actually its not rather it’s the remaining of the bone which have been further replaced by the inorganic minerals. Fossilization is nothing but the process of formation of the fossil from plants and animals. This is also called as rare, as very small fraction of the plants as well as the animals can be found that has been preserved as the fossil. The fossils are found are of hard parts like bones, shell or teeth. The tissue on burial gets altered.

organ system-an organ system is a group of organs that work together to perform one or more functions. each does a particular job in the body, and is made up of certain tissues.

layer 3 is younger than layer 6.