The diagrams below show fossils in undisturbed layers of sedimentary rock.

Question

Which diagram best represents a mass extinction event in the fossil record?
Choose 1 answer:
Choose 1 answer:
(Choice A) A diagram shows two rock layers, one shallower and one deeper. The shallower rock layer is on top of the deeper rock layer. The shallower rock layer contains two fossils. The deeper rock layer contains nine fossils.
A
A diagram shows two rock layers, one shallower and one deeper. The shallower rock layer is on top of the deeper rock layer. The shallower rock layer contains two fossils. The deeper rock layer contains nine fossils.
(Choice B) A diagram shows two rock layers, one shallower and one deeper. The shallower rock layer is on top of the deeper rock layer. The shallower rock layer contains three fossils. The deeper rock layer contains two fossils.
B
A diagram shows two rock layers, one shallower and one deeper. The shallower rock layer is on top of the deeper rock layer. The shallower rock layer contains three fossils. The deeper rock layer contains two fossils.
(Choice C) A diagram shows two rock layers, one shallower and one deeper. The shallower rock layer is on top of the deeper rock layer. The shallower rock layer contains nine fossils. The deeper rock layer contains two fossils.
C
A diagram shows two rock layers, one shallower and one deeper. The shallower rock layer is on top of the deeper rock layer. The shallower rock layer contains nine fossils. The deeper rock layer contains two fossils.

Answer 1

The diagram that best represents a mass extinction event in the fossil record is Choice C. This is because the shallower rock layer contains nine fossils, while the deeper rock layer only contains two fossils. This sudden decrease in the number of fossils between the two layers suggests a significant event that caused a mass extinction of many species.