"<span>b. The improvements in productivity in early agricultural societies enabled more complex societies to develop" would be the best option, since they had a surplus of food--meaning that people could focus on other jobs.</span>
It was a strategic point in the Tennessee River. The union wanted to gain control of the tributaries that flowed into the Mississippi River. Southern troops were not defending this place. It was a stronghold protecting the North.
Sharecropping<span> is a form of agriculture in which a landowner allows a tenant to use the land in return for a share of the crops produced on their portion of land.</span>
Urbanization happened because many occupations, factories, and businesses were located in the same area. People went to urban areas to find work, and therefore, created the need to have more space in urban areas. That is how cities of (urban areas) were formed. The late 1800's introduced the Industrial Revolution and created many jobs for people because of it. This eventually led to urbanization.
I hope this helps!
~cupcake
As the war dragged on, the Union's advantages in factories, railroads, and manpower put the Confederacy at a great disadvantage.