Answer:atmosphere
Explanation:Earth's atmosphere is a layer of gases surrounding the planet Earth and retained by the Earth's gravity. It contains roughly 78% nitrogen and 21% oxygen 0.97% argon and carbon dioxide 0.04% trace amounts of other gases, and water vapor. This mixture of gases is commonly known as air.
<span>C.by introducing female hormones that prevent the ovaries from releasing eggs</span>
The lower the fossil the older it is.
So, if two fossils were in different layers of sedimentary rock, the lowest fossil is older.
