Question

which layer of rock is the oldest?
1
2
3
4
complete
in which layer of rock would you find the oldest fossil?
1
2
3
4
done

Explanation:

In geology, the principle of superposition states that in undisturbed sedimentary rock layers, the oldest layer is at the bottom. So, the oldest rock layer and the oldest fossil (as fossils form within rock layers) would be in the lowest layer.

Answer:

For "Which layer of rock is the oldest?", the answer is 4. For "In which layer of rock would you find the oldest fossil?", the answer is 4.