Question

Curled up fossil trilobites tell us:

A. Their preferred resting position
B. The environmental conditions at the time
C. Their reproductive behavior
D. The cause of their death

Answer 1

Curled up fossil trilobites can suggest a mass extinction event.

Step-by-step explanation:

The question is asking for the likely reason paleontologists concluded that a particular layer in the excavated site correlates to a mass extinction. One possible reason for their conclusion is because the layer contains curled up fossil trilobites. These fossils suggest that the trilobites died suddenly and were quickly buried, which is a characteristic of mass extinction events. It is important to note that the answer is not definitive and other evidence would need to be considered to confirm the conclusion.