Answer:
Here's the answer with all the relevant time periods!
- Under the Missouri Compromise, Missouri was admitted as a slave state and Maine was admitted as a free state 1820
- The Mexican-American War ended with the United States gaining more than 500,000 square miles of Mexican territory 1846-1848
- Under the Compromise of 1850, California was admitted as a free state, and the territories of Utah and New Mexico were created 1850
- Abraham Lincoln was elected president of the United States 1860
- The Southern states formed a confederation known as the Confederate States of America 1860-1861
Step-by-step explanation: