Why do historians divide the past into eras?

Which of the following flow charts accurately illustrates the history of constitutional amendments in the united states?

Which group was responsible for determining the borders of african colonies and later countries

23. how does specialization among nations encourage interdependence? nations work together to share labor and resources to produce vital goods. nations sign treaties prohibiting taxes on imports. nations produce specific goods and then trade to obtain things they need. nations that are more developed agree to fund development in nations with limited industry.