What was the most significant development during reconstruction

Civil War Amendments--The 13th, 14th, and 15th Amendments were passed during Reconstruction changing the lives of blacks and whites in the South. 

The 13th Amendment ended slavery allowing blacks to work freely but also leaving plantations without workers. The 14th Amendment gave blacks citizenship and the 15th Amendment gave black men the right to vote. 

Probably japan. they got a really high life expectancy.

The answer would be a