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.
<em>Declining political participation as a result of the Enlightenment</em> 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<em> Significant increase in protections for American Indians through new treaties</em>. 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 <em>Rapid decline of political factions in light of an improving economy</em> is wrong because around 1829-1850 there was great grown with the Market Revolution, the improving of economy was not declined.
Well for some to list off, there's the Washing Machine, Microwave, ATMs, and one of the biggest changes being Radio by Ernst Alexanderson and Reginald Fessenden. There were also electronic televisions by Philo Farnsworth in 1923, later on to be adapted by your modern television creators like Sony and Sharp.
There's a lot of inventions that occurred during the 19th and early 20th centuries. I've only named a few. There's also during that time period advancements of Air Travel after<span> Orville and Wilbur Wright in 1903. As well as Military Tanks, advanced guns, gun silencers for the Military, as well of course, the Atomic Bomb in 1945.</span>
It true it was the spark and beginning of ww1