Plz, help what was the pax Romana a. all of ancient Romana history b. a period of Romana peace and property c. another name for the roman republic d. another name for the roman empire whoever answer will get brainiest

Two of these describe "federalism." (choose two answers) select one or more: a. the national government absolutely controls all state governments. b. power is shared by the national and state governments. c. state governments exercise absolute power over the national government. d. it is a compromise meant to eliminate the disadvantages of a "unitary" and a "confederate" system.