North Africa traded gold while the west Africans traded salt, so they each benefited
Some examples of this were the Fugitive Slave Act, Preston Brooks's attack on Charles Sumner, and the Dred Scott decision (the part of it which said that African Americans could never be citizens). None of these events tangibly hurt the North or the South.
Railroads on the Railways required tracks for the trains to run on them these tracks earlier made up of iron for its heavy duty but soon enough realise that iron was not a very good option for tracks. Meaning drawbacks of using iron for example rusting is it was realised that Steel was a better option in making railroads.
Steel being made out of iron is heavy duty material yet it is not much prone to rusting. Just addition of certain minerals and carbon in iron steel forging is done making it heavy duty material.
Motivations for colonization were to extract gold and silver from the Americans, to stimulate the Spanish economy and make Spain a more powerful country.Spain was also aiming to convert all native Americans to Christianity.
Hope this helped (:!!!
<u>respect</u>, NWO wanted to respect the rights of native american land as if they were a sovereign nation like the laws intended