Answer:
Option: They were railroad hubs and central to supply lines.
Explanation:
During the Civil War, the Union needed to keep hold of Chattanooga and Atlanta because these places were part of the railroad junction which remains as vital for supplying goods to the troops.
Atlanta became a target because of its unusual economic and political importance to the Confederacy. It was a significant railroad hub for the support for the war effort.
By studying the fossil record we can tell how long life has existed on Earth, and how different plants and animals are related to each other. Often we can work out how and where they lived, and use this information to find out about ancient environments. Fossils can tell us a lot about the past.