Question

a folded cross - section of a hillside is shown. which layer is the oldest?

Explanation:

According to the law of superposition in geology, in an undisturbed sequence of sedimentary rocks, the oldest layers are at the bottom. Even with folding, the original order of layering is maintained in a relative sense. Layer 1 is at the bottom - most position in the original sequence before folding.

Answer:

Layer 1