Most people in 1861 expected the North to easily defeat the South and quickly win the war. Why did the war last for four years, proving this assumption false?

People in the North and the South had been struggling against each other for so long ... parties, and patriotic speeches made it easy for both sides to recruit soldiers. ... Most people did not expect the war to last very long, so some ... men had joined the Union Army, most of them for two- or three-year terms.

Explanation:

radioactive dating, also known as  radioisotope dating  is a process that in  estimating the approximate  age  of  rocks. these data can be analyzed from  the studies dealing with the  decay of the radioactive elements that are present in these rocks. in nature, there are a few types of materials or atoms which are quite unstable and they spontaneously decay or breakdown to form other kinds of atoms.