In 1900, Mongolia was part of China.
However, in 1911, Mongolia became independent.
Answer:
The piece of evidence that would best support the claim that "all new territories to the US should decide for themselves whether they will be slave or free" is the Compromise of 1850, that established the precedent that new territories would choose for themselves whether to be slave or free.
Explanation:
The Compromise of 1850 was an agreement between the different states of the United States regarding the status with which the different territories obtained after the war with Mexico would enter the Union. The question was whether these states would be free or slave, and how this would affect the balance between the two groups of states in Congress. Finally, through this agreement California was admitted as a free state, while Utah and New Mexico could define their status through popular sovereignty. The most important part of this agreement was the acceptance of popular sovereignty as the defining method of determining the status of the states against slavery. This would be applied again after the sanction of the Kansas-Nebraska Act, which would lead to a prelude to the Civil War in the event known as Bleeding Kansas.
There were several immediate stated causes for the U.S. declaration of war: first, a series of trade restrictions, Orders in Council (1807), introduced by Britain to impede American trade with France, a country with which Britain was at war (the U.S. contested these restrictions as illegal under international law); second, the impressment (forced recruitment) of U.S. citizens into the Royal Navy; third, the British military support for American Indians who were offering armed resistance to the expansion of the American frontier to the Northwest. President James Madison and Congress declared what is sometimes referred to as the 2nd War of Independence, the War of 1812.
Vicksburg effects: The Battle of Vicksburg effected the Civil War because the Union got full control of the Mississippi river therefore taking over and shutting down the confederates trade, transportation, and military/fortifications.
