1. What are the 4 Eras’s? 2. What Era is the oldest? 3. How many periods are in the Paleozoic Era? 4. How many periods are in the Mesozoic Era? 5. What Era AND Period did the dinosaurs appear? 6. What Era do we live in? 7. How many periods are in the Cenozoic Era? 8. How many total periods exist? 9. What Period did all the dinosaurs die? 10. What Period do we in?