Answer:
Katherines oppurtunity cost is the cost of getting to the lecture event itself plus the reduction in her physics exam grade by not studying tonight.
Explanation:
"Return to normalcy" was United States presidential candidate Warren G. Harding's campaign slogan for the election of 1920. It evoked a return to the way of life before World War I, the First Red Scare, and the Spanish flu pandemic.
Answer:
system of checks and balances
Explanation: