the most important consequence of the election of 1800 is?

Question

a. that government control moved from one party to the other peacefully
b. Thomas Jefferson and Aaron Burr tied with 75 electoral votes each
c. that the US became less democratic
d. the House of Representatives elected Jefferson after John Adams had left Washington

Answer 1

The answer is a - Jefferson peacefully took power from Adams, a rather fierce political enemy.

Jefferson and Burr did tie, but that was not a consequence, merely a fact about the election -- they got 73 votes by the way.

The United States actually became significantly more democratic, as one of Jefferson's first acts was to repeal the Alien and Sedition Acts.

The House did elect Jefferson, but again, a fact, not a consequence.

For all the details, see:
http://en.wikipedia.org/wiki/U.S._presidential_election,_1800