Which of the following occurred in American society in the early 1800s?

Rapid decline of political factions in light of an improving economy

Increased support for social reform in spite of regional resistance

Declining political participation as a result of the Enlightenment

Significant increase in protections for American Indians through new treaties

The correct answer is Increased support for social reform in spite of regional resistance. Some of the social reform included public school for children; Declaration of Rights of the Women of the United States with the Suffrage movement; also the religious reform was important for the profound social reform.

Declining political participation as a result of the Enlightenment is wrong because democracy was broadened in early 1800, till then only Kentucky and Tennessee could elect and only white men and wealthy could vote, around 1820 eight states were participating in elections and other groups as free-men could vote, later with the ratification of the U. S. Constitution and the 15th Amendment African-Americans and women were also allowed to vote.

This answer is wrong Significant increase in protections for American Indians through new treaties. Around this period many American Indians went to war to protect their land from the white invasions and expansion, many Indians were killed by the whites. Even there were around 368 treats between US government and American Indians from 1776-1886 most of the treaties were about land, but these treaties required the Indians to cede their lands, others to give an annuity for the territory loss, by the time Indians could not purchase American lands so the treaties did not protect the Indians.

The option Rapid decline of political factions in light of an improving economy is wrong because around 1829-1850 there was great grown with the Market Revolution, the improving of economy was not declined.