1st Summative test

5. Evidence of an organism's activity, such as footprints, burrows, nest or trails.
9. determines the sequence of geologic events.
10. Organisms should be covered quickly by sediments
11. the natural process by which plant or animal remains are turned into stone or preserved over long periods.
12. Evidence of plants that lived on Earth millions of years ago.
14. Thin carbon outlines left behind when an organism is compressed overtime.
16. Radioactive element used for very old rocks, often billions of years old
18. An unstable atom that changes into another substance.
20. estimates their numerical ages.

1. Rocks containing the same fossils are generally the same relative age.
2. Sedimentary rocks are originally deposited in flat, horizontal layers.
3. The oldest rock layer is found at the bottom, while the youngest is at the top.
4. The organism is preserved almost unchanged
6. preserved remains of an organism, such as bones, teeth, and shells.
7. A fault cuts through several rock layers
8. The process in which unstable atoms break down over time.
13. A fossil formed when minerals fill a mold, creating a copy of the original organism.
15. The time required for half of the atoms in a sample to decay.
17. Bones, shells and teeth are examples of ___________.
19. A hollow impression left in rock after the original organism decays