The reason there was slavery in the United States is because there was more work to do than people to do it. The North's population grew quicker than the South's, so they could become "moral"quicker
An Automobile should be a possible answer i do hope this helps
The Aztecs built their settlement in a swamp in what is now Mexico City and when the Spanish arrived they thought it more spectacular than Venice. The Aztecs were fantastic warriors but they were also excellent farmers: because they had stumbled on hydroponics, their floating fields produced an abundance of nutrients in the food they were growing.
The Mayas built some of the tallest buildings of the ancient world – without the use of the wheel, or even horses. The pyramid El Castillo in Chichen Itza is the Mayan calendar, literally set in stone.
<span>the Incas lived in the mountains of South America and had to cross very deep ravines they invented the world's first suspension bridges in spite not having hemp or sisal ropes. They made their bridges out of twisted fibers of long stemmed grass, another amazing feat of ingenuity from an inspired region.</span>
<span>Hope this help :)..........my hand hurts.</span>
Richard the lion hearted<<<<
<em>Answer</em>
<em>By not getting involved in it, that's what I do most of the time...</em>
<em>Explanation</em>
<em>Hope this helps :')</em>
