Please help me Write a 1-3 sentence summary that highlights the key point of this fact below

The issues of slavery and central power divided the United Sates. Slavery was the law of the land, north and south, until the early 19th century. It was concentrated in the southern states, where slaves were used as farm laborers and formed the backbone of the southern economy. In the northern states, where industry drove the economy, many people believed that slavery was immoral and wrong. Southerners felt threatened by these northern "abolitionists” and claimed
that the common government had no power to end slavery against the wishes of the states. Eventually, southerners became convinced that the common government
would attempt to abolish slavery nation-wide. Eleven states left the United States
in the following order and formed the Confederate States of America: South
Carolina, Mississippi, Florida, Alabama, Georgia, Louisiana, Texas, Virginia,
Arkansas, North Carolina, and Tennessee.

1.) wen ti, an emperor of the dynasty, looked to the han dynasty for methods of control and order. sui tang song yuan 2.) the pagodas built during the song dynasty were influenced by which structures? egyptian pyramids mesopotamian ziggurats indian stupas islamic mosques 3.) what was the term for a chief of a mongol clan? temuchin khan emperor tsar 4.) although the mongols used brutal force to establish an empire, once they had places under their control, they ruled peacefully. true false 5.) who was the venetian man who kublai khan sent on many travels-missions which were later recounted in writing, though some now doubt whether these missions actually happened? vasco de gama. marco polo matteo ricci carlo amoretti 6.) southeast asia consists of a mainland region and an island region-which of the following countries is part of the mainland region? singapore indonesia philippines myanmar (burma) 7.) the japanese belief in natural spirits eventually developed into a religion known as shinto, or yin and yang. path of the shrine. way of the kami. honoring torii. 8.) in which modern-day country in southeast asia did the chinese conquer territory in 111 bc, leading to a period of chinese rule that did not end until a rebellion occurred in 939? vietnam cambodia malaysia thailand 9.) which of the following was an achievement of the khmer empire? the invention of a cannon that used gunpowder development of moveable type made of metal pieces advances in horsemanship, including the invention of the stirrup construction of an irrigation system covering millions of acres of land 10.) the pagan kingdom developed along which river in myanmar (burma)? mekong irrawaddy saigon ganges