Question

part a
for each set of statements below, write m before the main idea and s before the statements that support or help to explain the main idea. one statement in each set does not support or explain the main idea; write x next to this statement.
set 1
in the 1870s investors migrated to the economically devastated south.
reconstruction governments established the souths first state - supported public school system.
reconstruction governments left a record of achievements in the south.
state governments in the south repealed the black codes and developed a more equitable tax system.
set 2
many sharecroppers were exploited and fell into debt because they were unable to pay merchants who had advanced them credit.
congress passed enforcement acts in 1870 and 1871 to outlaw terrorist societies.
new economic patterns kept many small farmers in a state of poverty and prevented the south from diversifying its economy.
plunged into poverty by wartime destruction, many southern farmers were forced to pledge future crops against loans and to grow cotton instead of food crops.
set 3
reconstruction opponents used violence to try to restore white supremacy in the south.
the ku klux klan was responsible for beating and lynching african americans, northerners, and scalawags.
sharecroppers generally paid rent with a share of a years crops.
white supremacists threatened that black workers who supported reconstruction at the polls would be dismissed from their jobs.
set 4
reconstruction brought both a political and a social revolution to the south, but it failed to bring an economic revolution.
although reconstruction had in some ways been a success, it was also a failure.
few african americans managed to achieve economic independence during the period of reconstruction.
radical reconstruction ended after the democrats regained control of state governments in the south in 1877.

Explanation:

For Set 1, the main idea is about investors migrating to the South in the 1870s. The statements about Reconstruction - era educational, legal, and tax - related achievements are supporting details, while the broad statement about Reconstruction government achievements is too general and not directly related.
For Set 2, the main idea could be about the economic hardships of sharecroppers and Southern farmers. The statement about Congress passing enforcement acts is not related to this economic theme.
For Set 3, the main idea is about violence and intimidation by white supremacists during Reconstruction. The statement about sharecroppers paying rent with crops is not related to this violence theme.
For Set 4, the main idea is about the political, social, and economic impacts of Reconstruction. The statement about the end of Radical Reconstruction is a supporting detail about the political aspect.

Answer:

Set 1: M. In the 1870s investors migrated to the economically devastated South.; S. Reconstruction governments established the South’s first state - supported public school system.; X. Reconstruction governments left a record of achievements in the South.; S. State governments in the South repealed the Black Codes and developed a more equitable tax system.
Set 2: S. Many sharecroppers were exploited and fell into debt because they were unable to pay merchants who had advanced them credit.; X. Congress passed enforcement acts in 1870 and 1871 to outlaw terrorist societies.; S. New economic patterns kept many small farmers in a state of poverty and prevented the South from diversifying its economy.; S. Plunged into poverty by wartime destruction, many Southern farmers were forced to pledge future crops against loans and to grow cotton instead of food crops.
Set 3: S. Reconstruction opponents used violence to try to restore white supremacy in the South.; S. The Ku Klux Klan was responsible for beating and lynching African Americans, Northerners, and scalawags.; X. Sharecroppers generally paid rent with a share of a year’s crops.; S. White supremacists threatened that black workers who supported Reconstruction at the polls would be dismissed from their jobs.
Set 4: M. Reconstruction brought both a political and a social revolution to the South, but it failed to bring an economic revolution.; S. Although Reconstruction had in some ways been a success, it was also a failure.; S. Few African Americans managed to achieve economic independence during the period of Reconstruction.; S. Radical Reconstruction ended after the Democrats regained control of state governments in the South in 1877.