Why is there a system of checks and balances?

Need it now explain gorbachev’s policy of glasnost. how did this policy change the soviet union?

How did margaret thatcher de-escalate the cold war

Why was the sixteenth amendment important to woodrow wilson’s efforts to regulate the economy? a) the sixteenth amendment lowered interest rates charged by banks. b) the sixteenth amendment allowed congress to levy an income tax c) the sixteenth amendment lowered tariffs on imported goods d) the sixteenth amendment allowed congress to break up monopolies