Respuesta :
B. Paleozoic
Explanation
Rocks were first found and studied in Mesozoic era, era after Cenozoic and before Paleozoic. Rocks of this age was first studied in Paleozoic era. To be specific, Permian period of Paleozoic era was the period where rocks of this age was first studied.
In Devonian and Cambrian period under Paleozoic era, the rocks of this age was also studied. The layers of rock aid in understanding the history of geological events that had occurred.
