How do historians identify one era as separate from another era

They identify eras based on the events that occurred in that era.

Explanation:

For example, classic music was popular during the 1750-1820 so it's called the Classic Era. The 1950s-1990s was known as the Civil Rights Era. And what we all are experiencing now which is 2020-indefinite time, which is known as the Corona-virus Era.

it was the new england colonies.

hope dis !

the communist manifesto is an 1848 political pamphlet by the german near the end of the manifesto, the authors call for a "forcible overthrow of all existing social conditions",  ..