Answer: B. Abolitionist Movement
Spread of religion and political views
Answer: Checks and balances.
Explanation: The whole point of establishing a system of checks and balances was to prevent one of the branches of government from getting too powerful. In order to prevent this, each branch of government has the power to stop another branch of government in the event that they are abusing their powers. In the executive branch (the president), this includes the ability to veto bills. In the judicial branch (Supreme Court), this includes the power to declare an action unconstitutional. And in the legislative branch (Congress/Senate), they have the power of impeachment.
It was important because it proposed a completely different view of the universe and the position of the Earth and Sun within it. Prior to Copernicus, it was thought that the Earth was stationary and that everything in our galaxy revolved around it. However, the heliocentric model proposed a different view - it means that the Sun is actually the center of the galaxy, and everything within the Milky Way, including the Earth, revolves around that star.
The severe recession that began in December of 2007 was caused by the bursting of the housing bubble and the re- sulting credit crisis.