Question

2. During which Epoch did humans first appear?Holocene3. How many million years ago did humans first appear?2.8 million years ago4. What are the three periods of the Mesozoic Era?Cretaceous, Jurassic, Triassic5. When did dinosaurs first appear?Triassic period6. In what period did birds first appear?Jurassic7. During what period did the dome-like uplift of the Adirondack region begin?

Answer 1

(1)

The three eras within the Phanerozoic eon are

1) The Paleozoic era (541 million to 252 million years ago)

2) The Mesozoic era (252 million to 66 million years ago)

3) The Cenozoic era (66 million years ago to the present)