Which region can be described as rolling flatlands with many rivers, broad river valleys, and grassy hills?

Which region has rugged mountains along the Pacific Coast that stretch from California to Canada; Contains fertile valleys?

Which region can be described as flat grasslands that gradually increases in elevation westward?

Which region is located along the Atlantic Ocean and Gulf of Mexico with broad lowlands providing many excellent harbors?

Which region is wrapped around the Hudson Bay in a horseshoe shape with hills worn by erosion and hundreds of lakes carved by glaciers, and holds some of the oldest rock formations in North America?