Help please.
List of important events in American History:
1820 – Missouri Compromise
1820 – Maine becomes a state
1820 – U.S. presidential election, James Monroe re-elected president, Daniel D. Tompkins vice-president.
1821 – Missouri becomes a state.
1823 – Monroe Doctrine proclaimed.
1825 – John Quincy Adams elected president by The House of Representatives; John C. Calhoun becomes vice-president
1825 – Erie Canal completed
1826 – Former presidents Thomas Jefferson and John Adams die within hours of each other on Independence Day
1828 - South Carolina Exposition and Protest published during the Nullification Crisis
1828 – Baltimore and Ohio Railroad construction begun
1828 – U.S. presidential election
Write two or three sentences about each event explaining why this event is important and how it affected America.