Q: What is the major unit of geologic time?

Flexi Says:

• Geologic Time Scale divisions mark major events which highlight changes in climate, geography, atmosphere, and life.
• The largest units of time are eons; the 4.6 billion years of earth’s history are divided into four eons.
• The Phanerozoic Eon includes the most recent 545 million years and the most detailed fossil record.