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 youngest layer is on top and each layer is younger than the layer beneath it. This principle helps in determining the relative ages of rock layers. The first option describes the law of original horizontality. The third option is related to the principle of cross - cutting relationships. The fourth option is about the deformation of rock layers (not directly the law of superposition).

Answer:

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