I would say 30,000 cause all the next developments were from the 1860's forward and that is when huge growth happened, after 1860.
Slavery started because people couldn't do their jobs themselves, so they had other people do it for them.
Answer:
Roads, language, and creation of the arch
<em>or </em>
1, 2, and 5
let me know if im wrong, I didn't include roads on my test but got it wrong.
