One factor essential to the development of early civilization was the use of a standard medium of exchange.
the use of a standard medium of exchange.

the taking of an annual census.
the taking of an annual census.

the emergence of a distinct caste system.
the emergence of a distinct caste system.

the ability to produce surplus food

yes i can of course like what is it gonna be about

from the conditions of the working class in england by friedrich engels,the main idea is :

map scale refers to the relationship (or ratio) between distance on a map and the corresponding distance on the ground. for example, on a 1: 100000 scale map, 1cm on the map equals 1km on the ground.

when she faked her death and the readers knew but romeo didn't.