Question

which statement describes the law of superposition?
sedimentary rocks were originally in horizontal layers.
in horizontal rock layers, each layer is younger than the one below it.
rock layers must be in existence before something can happen to them.
rocks that are not in horizontal layers were shifted by some geologic event.

Explanation:

The law of superposition states that in undisturbed horizontal sedimentary rock layers, the younger layers are on top of the older layers.

Answer:

In horizontal rock layers, each layer is younger than the one below it.