6. Scientists discovered a cross-section of rock with several fossils showing in different places in the cross-section. How can the scientists compare the relative ages of the fossils? (1 point)
The fossils that are smaller are older.
The fossils in upper layers are younger.
The fossils in darker rock layers are older.
The fossils that are more intact are younger.
To compare the relative ages of fossils in a cross-section of rock, scientists use a principle called the Law of Superposition. According to this law, in undisturbed rock layers, the youngest rocks are found on top while the oldest rocks are found at the bottom. This principle is based on the understanding that over time, sedimentary layers are laid down and accumulate, with the oldest layers being at the bottom and younger layers on top.
Applying this principle to fossils in a cross-section of rock, scientists can determine the relative ages of the fossils based on their position within the rock layers. Therefore, the correct answer is:
- The fossils in upper layers are younger.
By examining the position of the fossils within the rock layers, scientists can infer a relative age relationship, indicating whether one fossil is older or younger than another. It is important to note that this method provides relative ages and not absolute ages. To determine the absolute age of a fossil, additional techniques like radiometric dating may be required.