The nation that did not attend was Russia.
Mass production!!!!!!!!!!!
I believe the answer is: The establishment of sedentary village communities.
Southern statesmen wanted slaves to count while calculating which how many representatives a state would get (that way, southern states would have more representation) and northern statesmen wanted slaves to not count while calculating representation (that way the north would have more)
3/5th was the compromise--- each slave counted as 3/5th of a person.