Final answer:
The correct response is that scientists describe long ago events in the context of both a geological time scale and a timeline consisting of eons, divided into eras and periods. This encompasses the answer choices A and C. The geological time scale organizes Earth's history into eons, eras, periods, epochs, and ages based on significant geological and biological events.
Step-by-step explanation:
Scientists describe long ago events in the context of a geological time scale and a timeline consisting of eons, divided into eras and periods, and further subdivided epochs and ages. Thus, the correct answer is Both A and C are correct.
The geological time scale is a system of chronological dating that relates geological strata to time. This scale is used by geologists and other scientists to describe the timing and relationships between events that have occurred during the history of the Earth. At the broadest level, time is categorized into several principal eons: the Hadean, Archean, Proterozoic, and Phanerozoic. The latter three are part of what's known as the Precambrian super eon. Within these eons are eras, which are subsequently divided into periods, epochs, and ages.
Each unit of time on the geological scale is defined by significant events like extinctions, major climatic changes, or significant developments in the evolution of life. The use of radiometric dating of rocks and fossils provides the numerical ages associated with these geological time divisions. Understanding this hierarchical structure of time helps geologists and paleontologists to organize Earth's history in a detailed and meaningful way.