Question

students on a field trip to a fossil park each find a fossil they are able to take home. the field trip guide shows the students a diagram indicating the layer of the earth where each student’s fossil was originally created. which correctly identifies the oldest fossil and reason why it is the oldest?

surface layer

layer a (alexander’s fossil)

layer b (brittany’s fossil)

layer c (cole’s fossil)

layer d (devonte’s fossil

a. alexander’s fossil because it was formed directly underneath the surface layer.

b. brittany’s fossil because it was the darkest in color.

c. cole’s fossil because it provides evidence of ancient sea creatures before life moved onto land.

d. devonte’s fossil because it was formed in the deepest layer.

Explanation:

To determine the oldest fossil, we use the principle of superposition in geology (a concept in Natural Science, specifically related to Earth Science/Geology). The principle states that in undisturbed sedimentary rock layers, the oldest layers are at the bottom (deepest) and younger layers are on top.

• Option A: Alexander’s fossil is in Layer A (near the surface), so it’s young, not old. Eliminate A.
• Option B: Color of the fossil doesn’t determine its age. Eliminate B.
• Option C: The reason about sea creatures vs. land life isn’t related to the layer’s depth (the key here is layer position for age), and we don’t know Cole’s layer depth from the option’s reasoning. Eliminate C.
• Option D: Devonte’s fossil is in Layer D, the deepest layer. By superposition, the deepest layer is the oldest because it was deposited first. This matches the geological principle.

Answer:

D. Devonte’s fossil because it was formed in the deepest layer.