Why was Sumer more easily invaded than Egypt?

Which statements correctly identify a condition that must exist for a culture to be considered a civilization

Is the weather changing? consider the data of severe weather that includes tornadoes occurring throughout the u. s. over the last four years. compare the severe weather for the last three years. then compare the first three months of 2017 with that data. based on previous years, what might the prediction be for weather during 2017?

How does the balance of trade look different in the us today vs hot it looked in the 70's