In the first one, we have roads and bridges. While some other public works projects such as statues and archetecture give evidence of artistic genius, these generally are more utilitarian.

Social classes were growing up long before these projects, and have continued to this day, and job specialization also began prior to these projects, although some new specializations did grow out of them.

That leaves us with the answer that, even though they were useful and may have allowed a heightened standard of living for the cities, they were certainly costly in both human labor and lives.

Next question, regarding changes in ancient civilizations.

While the establishment of a civilization could be argued to be a significant change, and certainly the development of writing is also a significant change, neither of these changes happened often enough to qualify as “most often”. The same can be said for the creation of vast empires.

All of these are huge changes, but very rare occurances. So, we’re left with the answers of “shifts in their physical environment” which, while also rare, happened more often than the other causes already noted, and “interactions among people” which is a very common and highly dynamic function.

I would, however, caution you to look over the textbooks your daughter is using. Were I taking a college level class, this would be my argument, and I’d stick to it. In college level courses, the instructors often give ambiguous questions and grade based on your reasoning.

High school and middle school classes often simply expect you to parrot the textbook, and while I always got great pleasure from being able to defend my answers, sometimes it is easier to simply give the answer that the teacher expects.

And some of those high school and middle school textbooks are pretty poorly written.