Which era is sometimes referred to as the "age of mammals"?

The united states government was in debt from its beginning. how did the u.s. get into debt, and whom did it owe money?

Which of the following was an effect of allied defeats and high casualty rates on the eastern front? the united states issued the fourteen points. russia entered the war on the allied side. the united states entered the war sooner. russia experienced a revolution and dropped out of the war.

Which source would best a historian understand the effect of the great chicago fire on families? a. a biography of a chicago family displaced by the fire b. a letter from a grandmother in new york to her family in chicago c. a newspaper editorial about families who were displaced d. an oral history dictated by an adolescent who fled the fire