Cities first appeared in the southern region of this land with the earliest dating back to about 3500 B. C.E. These were similar to small, independent countries. Each had their own
ruler, as well as their own farmland to provide food. Suppose that you were visiting one of
these early cities. You would see a walled settlement surrounded by farmland used to
supply food for the city, as well as strong city walls constructed with sunbaked bricks.
Moats, or ditches filled with water, would surround these walls and help keep out
enemies. During an attack, people living outside the city walls would flee inside for
protection.

what is An important idea in the paragraph above ?

According to the federal regulations, which of the following studies meets the definition of research with human subjects? a researcher conducts a comparison of the comments made in a publicly available blog and the blogger's comments on a similar topic in a weekly magazine. undergraduate students in a field methods class are assigned a research question and asked to interview another classmate, to be followed by a class discussion on interview techniques. a cognitive psychologist enrolls undergraduate students for a computer-based study about the effect of mood on problem-solving behaviors. a researcher sets up a meeting with the superintendent of a large and diverse public school system to get data about the ethnic composition of the school system and the number of students receiving free lunches.