The process of rebuilding a society in the south was known as

The process of rebuilding a society in the south was known as reconstruction.

Explanation:  

The period in American history between 1863 and 1871 is called the reconstruction era. This era was a post war period and addressed various questions of formation of the Union.

The congress attempted for transforming the eleven confederate states into the union. It also ended slavery and the newly freed slaves were guaranteed civil rights.

Three constitutional amendments were made to for this. Confederate states were the southern states and reconstruction era aimed at transforming these states which has earlier declared secession.  

acid rain is the answer