Which of the following is defined as "a plan of a study that organizes observations in such a way as to establish a sound logical basis for causal inference"?

Preemption legislation would have to be based on which clause of the U.S. Constitution

a. Commerce b. Due Process c. Equal Protection d. Full Faith and Credit e. Supremacy

How does the spread of democracy promote the cause of peace?

a. Democracies have better trained diplomats. b. Democracies have a habit of handling conflict peacefully. c. Democracies use humanitarian aid to benefit other nations. d. Democracies understand their own national interest clearly.