Why was a cheeks and balance system set up in the constitution?

The U.S. System of Checks and Balances

In addition to this separation of powers, the framers built a system of checks and balances designed to guard against tyranny by ensuring that no branch would grab too much power

The Constitution divided the Government into three branches: legislative, executive, and judicial. Just like the phrase sounds, the point of checks and balances was to make sure no one branch would be able to control too much power

a big wall across the mexican border so no drugs, terrorist, or illegal immigrants can come through : )    

the correct answer is:

b) a rich merchant.