| Answer | Crossword Clue |
|---|---|
| CENOZOICERA | It began with the Tertiary Period |
| STONEAGE | It began with the Paleolithic period |
| tertiaries | The Tertiary period or the system of rocks deposited during it |
| ATOMICAGE | It began with the Manhattan Project |
| SPACETIMECONTINUUM | It began with the Big Bang |
| MIDDLEKINGDOM | It began with the 11th dynasty of ancient Egypt |
| MSNBC | It began with the slogan "It's time to get connected" |
| TWOPARTYSYSTEM | In the United States, it began with the Democratic-Republicans and the Federalists |
