"We must adjust to changing times and still hold to unchanging principles (Paragraph 20). How does the quote from Carter's teacher contribute to the text?

2686-2181 bce-- "egyptian civilization developed along the nile river in large part because the river’s annual flooding ensured reliable, rich soil for growing crops."

1069-664 bce-- "ancient egyptians developed wide-reaching trade networks along the nile, in the red sea, and in the near east."