<span>B.They introduced the idea that each nation had its own unique abilities.</span>
It was the Mongols that invaded Russia
The development of small villages into the first cities was known as "<span>b. Urban revolution," although this should not be confused with a more modern term in which people congregate more in pre-existing cities. </span>
The cotton gin made it easy for slaves to separate seeds out of the cotton. However, it it increased slave usage all over. It actually increased the use of slavery. The cotton gin just made one part of a slaves job quicker and easier.
The farm land of the Fertile Crescent that made agriculture easy for the people.
