Do you think the development of writing was important to
the success of Sumer as a civilization?

Yes

Explanation:

The increasingly sophisticated system of writing that developed also helped the civilization develop further, facilitating the management of complex commercial, religious, political, and military systems. The earliest known writing originated with the Sumerians about 5500 years ago.

answer; people where able to travel across the u.s.a faster than any other mode of transportation,travel time was about a week,from coast to coast