Answer:
Most fossils are found in sedimentary rocks, those rocks produced by the accumulation of sediment such as sand or mud. Wind and other weathering conditions wash away sediment on land, depositing it in bodies of water. For this reason, fossils of sea creatures are more common than those of land creatures.
Explanation:
I believe you are talking about Stem Cells.
Homeostasis, it is the process of organisms regulating their internal conditions. <span />
It is 200 million years because it has been around for a long time.