Question

a geologist finds four layers of sedimentary rock. she determines that no geologic events have shifted the layers. she labels the layers a, b, c, and d from the top to the bottom. which statement about these layers is accurate? a a is older than b. b b is older than c. c c is younger than a. d b is younger than d.

Explanation:

In undisturbed sedimentary rock layers, the principle of superposition states that the oldest layers are at the bottom and the youngest are at the top. Since the layers are labeled A, B, C, D from top - to - bottom, layer A is the youngest and layer D is the oldest. So A is younger than B, B is younger than C, and C is younger than D.

Answer:

C. B is older than C.