Question

the table lists several common organisms found in different layers of a rock labeled x, y, and z.
based on the table, four students each develop a model to represent the geological time scale by marking the different layers of rock in order of occurrence.
which model correctly organizes the layers of the rock on the geological time scale? model

Explanation:

In geological time scale, the principle of superposition states that in undisturbed sedimentary rock layers, the oldest layers are at the bottom and the youngest are at the top. Looking at the organisms:

• Layer X has the oldest - appearing organisms (tribolites, brachiopods, and other invertebrates).
• Layer Y has organisms (reptiles and dinosaurs) that appeared after the invertebrates but before mammals.
• Layer Z has the youngest - appearing organisms (mammals and humans).

So the order from oldest (bottom) to youngest (top) should be X (oldest) at the bottom, then Y, then Z (youngest) at the top. Model 4 has the correct order of X (bottom layer), Y (middle layer), and Z (top layer).

Answer:

Model 4.