Checks and Balances
                         
Executive,  Legislative, Judicial,

http://www.factmonster.com/ipka/A0777009.html

http://www.regentsprep.org/regents/ushisgov/themes/government/checks.htm

http://www.congressforkids.net/Constitution_checksandbalances.htm

http://www.congressforkids.net/games/checksandbalances/2_checksandbalances.htm

http://mrbruceshistory-2010.wikispaces.com/Checks+and+Balances+08

http://historyclassroom.com/_wsn/page2.html