The diagram below shows a sequence of rock layers. Examine the diagram, and answer the question that follows. Using radiometric dating, scientists have determined that Layer M is 110 million years old. Based on this information and the principle of superposition:

Question



(1 point)
Responses

Layer T is younger than 110 million years, and Layers R, X, and G are older than 110 million years.
Layer T is younger than 110 million years, and Layers R, X, and G are older than 110 million years.

Layers T, R, X, and G are all younger than 110 million years.
Layers T, R, X, and G are all younger than 110 million years.

Layers T, R, X, and G are all older than 110 million years.
Layers T, R, X, and G are all older than 110 million years.

Layer T is older than 110 million years, and Layers R, X, and G are younger than 110 million years.

Answer 1

Based on the principle of superposition, in a sequence of undisturbed sedimentary rock layers, the oldest layers are at the bottom and the younger layers are at the top. Given that Layer M is 110 million years old and is in the middle of the sequence, it can be inferred:

• Layers below Layer M (which would be layers R, X, and G) are older than Layer M and therefore older than 110 million years.
• Layer T, which is above Layer M, is younger than Layer M and therefore younger than 110 million years.

Thus, the correct response is:

Layer T is younger than 110 million years, and Layers R, X, and G are older than 110 million years.