Question

While examining a layer of rock, a scientist found a fossil of a trilobite like the one shown below. The scientist knows that trilobites only lived during the Paleozoic era.



The scientist finds fossilized remains of other species in the same rock layer as the trilobite. What can the scientist conclude about these other fossils?
A.
The organisms that formed them must have evolved from trilobites.
B.
The organisms that formed them likely went extinct before the Paleozoic era.
C.
The organisms that formed them likely also lived during the Paleozoic era.
D.
The organisms that formed them are still living in modern times.

Answer 1

C. The organisms that formed them likely also lived during the Paleozoic era.

Reason: Fossils found in the same rock layer are generally from organisms that lived at the same time. Since trilobites lived only during the Paleozoic, other fossils in that layer are also most likely Paleozoic in age.